Arbitration Clauses in Türkiye–UK Contracts: Istanbul or London After the Arbitration Act 2025

Most Türkiye–UK commercial contracts are negotiated clause by clause on price, delivery, warranties and liability.

The dispute resolution clause is often settled last, and sometimes copied from a previous transaction.

Yet that clause decides where a dispute will be heard and which national court will supervise it. It identifies the law that decides whether the clause itself is valid. And it largely determines whether an award can be turned into payment where the counterparty's assets are located.

On 1 August 2025, the Arbitration Act 2025 came into force in England and Wales and Northern Ireland. For cross-border contracts, its most significant change is a new statutory rule on the law that governs an arbitration agreement.

The rule it replaced had been set by the UK Supreme Court in 2020 in Enka v Chubb. In that case, the Turkish contractor Enka obtained an anti-suit injunction to protect a London arbitration clause.

For parties contracting between Türkiye and the United Kingdom, the change is practical. Take a Turkish-law contract with a London seat, or an English-law contract with an Istanbul seat. The law that now governs the arbitration clause may not be the one the parties assumed when they signed.

This article explains how Turkish and English law approach the arbitration clause, and where the two systems now converge or may still diverge. It then turns to the choice between an Istanbul and a London seat, and to the drafting points that decide whether the clause will work in both systems. It complements our guide to enforcing foreign judgments and arbitral awards in Türkiye, which deals with the final stage of the process.

1. An arbitration clause is a separate agreement with its own governing law

Both legal systems treat the arbitration clause as an agreement distinct from the contract in which it appears.

Under English law, section 7 of the Arbitration Act 1996 provides that, unless the parties agree otherwise, an arbitration agreement is not to be regarded as invalid, non-existent or ineffective because the main contract is.

Under Turkish law, Article 4 of International Arbitration Law No. 4686 (MTUK) and Article 412 of the Code of Civil Procedure No. 6100 (HMK) contain the same principle. A party cannot resist arbitration by arguing that the main contract is invalid.

Because the clause is a separate agreement, it can be governed by a law different from the law of the main contract.

That law answers questions that often decide an arbitration before the merits are reached:

• whether the clause was validly concluded;
• which disputes it covers;
• whether it binds an affiliate or assignee that did not sign it; and
• whether a pre-arbitration step was a condition of the right to arbitrate.

In a Türkiye–UK contract there are usually at least three candidate laws: the law chosen for the main contract, Turkish law and English law. Which of them applies can be decisive.

2. The Arbitration Act 2025 moved the default to the law of the seat

The Arbitration Act 2025 received Royal Assent on 24 February 2025. Its substantive provisions came into force on 1 August 2025 under the Arbitration Act 2025 (Commencement) Regulations 2025.

It inserted a new section 6A into the Arbitration Act 1996. Under section 6A, the law applicable to an arbitration agreement is:

• the law that the parties expressly agree applies to the arbitration agreement; or
• where there is no such agreement, the law of the seat of the arbitration.

Section 6A(2) adds the qualification that matters most in practice. An agreement that a particular law governs the main contract does not constitute an express agreement that the same law governs the arbitration agreement.

This reverses the starting point adopted in Enka v Chubb. Under Enka, a choice of law for the main contract would generally also apply to the arbitration clause. Only where no law had been chosen would the court usually apply the law of the seat, as the law most closely connected with the arbitration agreement.

The new rule does not apply to arbitration agreements derived from standing offers to arbitrate contained in treaties or in the legislation of a country outside the United Kingdom. That exception mainly concerns investment treaty arbitration.

Two features of the reform are particularly relevant to Turkish parties.

First, section 6A applies even where the seat is outside England and Wales or Northern Ireland. The 2025 Act added it to the provisions of the 1996 Act that apply regardless of the seat. An English court considering a clause with an Istanbul seat therefore starts from the same rule.

Second, under section 17 of the 2025 Act, the amendments apply in relation to arbitration agreements whenever made. They do not apply to arbitral proceedings commenced before 1 August 2025, or to court proceedings connected with them. A clause signed in 2018 will therefore be read under section 6A if the arbitration starts now.

The 2025 Act made other changes as well, discussed below. It introduced a statutory duty of disclosure for arbitrators, a power to make awards on a summary basis and express support for emergency arbitrators. It also clarified the court's powers in relation to third parties and narrowed the framework for jurisdictional challenges.

3. Turkish law reaches a similar default by a different route

For international arbitration seated in Türkiye, Article 4 of the MTUK sets a two-step test. The arbitration agreement is valid if it complies with the law the parties chose to apply to it or, in the absence of such a choice, with Turkish law. The structure resembles section 6A: a choice made for the clause first, otherwise the law of the seat.

The enforcement rules follow a similar logic. Under Article 62(1)(e) of Law No. 5718 on International Private and Procedural Law (MÖHUK), a Turkish court may refuse to enforce a foreign award if the arbitration agreement is invalid under the law to which the parties subjected it. Failing such an agreement, the test is the law of the country where the award was made. Article V(1)(a) of the New York Convention follows the same pattern.

Since the English default moved to the seat, the two systems point in the same direction in many ordinary cases. Three common structures illustrate the point:

• Turkish-law contract, London seat. Under section 6A, an English court will apply English law to the arbitration clause unless the parties expressly chose another law for the clause. A Turkish enforcement court will apply English law as well, unless it finds that the parties subjected the clause to another law.
• English-law contract, Istanbul seat. The MTUK points to Turkish law unless the parties chose a law for the clause, and an English court applying section 6A will reach the same result. Parties who assumed that English law governed every aspect of their contract may find that the validity and scope of their arbitration clause are governed by Turkish law.
• Express law of the clause. Where the clause itself states the law that governs it, both systems will generally give effect to that choice, subject to their own rules on arbitrability and public policy.

4. The two systems can still disagree on what counts as a choice

The convergence has a weak point. Section 6A(2) tells an English court to disregard the main contract's governing-law clause when identifying the law of the arbitration agreement. The New York Convention test applied by Turkish courts at the enforcement stage contains no such instruction.

Under that test, the question is whether the parties gave any indication of the law to which they subjected the arbitration agreement. In Kabab-Ji v Kout Food Group, decided before the 2025 Act, the UK Supreme Court held that a general choice-of-law clause in the main contract would normally be a sufficient indication for that purpose.

If a Turkish court reads the Convention in the same way, a Turkish-law contract with a London seat could have its arbitration clause assessed under English law in London and under Turkish law in Türkiye. On most questions the answer will be the same. On issues such as who is bound by the clause, how far its scope extends or whether a defective clause can be saved, it may not be.

The simplest way to remove that risk is to state the law of the arbitration agreement expressly in the clause itself. Both systems then look to the same law from the outset.

5. The seat is a legal choice, not a venue

The seat is the legal home of the arbitration. It determines which national arbitration law governs the procedure, which courts supervise the tribunal, where an award can be set aside and, for New York Convention purposes, where the award is made.

The seat is not the same as the hearing venue. Both the ISTAC Rules and the LCIA Rules allow hearings to be held away from the seat. An arbitration seated in London can hold its hearing in Istanbul, and the reverse.

For Türkiye–UK contracts, the choice usually comes down to Istanbul or London. Neither is right for every contract. The relevant factors are practical.

Where enforcement is likely to take place. If the counterparty's assets are in Türkiye, a London award must be recognised and enforced by a Turkish court under the New York Convention and Articles 60 to 63 of the MÖHUK. Türkiye has been a party to the Convention since 1992, with declarations limiting its application to awards made in another Contracting State and to disputes considered commercial under Turkish law. The United Kingdom is also a Contracting State, so the reciprocity declaration is not an obstacle.

Enforcement may be refused only on limited grounds, including invalidity of the arbitration agreement, lack of proper notice, an award exceeding the arbitration agreement, non-arbitrability under Turkish law and public policy. The application must be accompanied by the arbitration agreement and the award, in the original or certified copies, with certified translations. Under Article 60(2) of the MÖHUK, the parties may agree in writing on the place of the Turkish court that will hear the application. Otherwise, jurisdiction follows the domicile or residence in Türkiye of the party against whom the award was made or, failing those, the location of assets available for enforcement.

What happens after the award. Choosing London does not avoid Turkish courts where the assets are in Türkiye. It changes the type of proceedings that take place there. Under Article 57(2) of the MÖHUK, applied to arbitral awards through Article 61(2), an appeal against a decision on enforcement suspends its execution.

For an international award made in Istanbul, the route is different. Under Article 15 of the MTUK, the losing party may bring an annulment action before the competent regional court of appeal within 30 days of notification of the award. Filing that action automatically suspends enforcement. A further appeal to the Court of Cassation is available, limited to the annulment grounds. A certificate of enforceability is issued once the rejection of the annulment action has become final.

Supervisory court. For a London seat, the supervisory court is the English High Court, usually the Commercial Court. Court challenges are limited to substantive jurisdiction (section 67), serious irregularity (section 68) and, unless excluded, appeal on a point of law (section 69). The LCIA and ICC Rules contain waivers of recourse that are generally understood to exclude appeals on points of law. For an Istanbul seat, the annulment grounds in Article 15 of the MTUK largely follow the UNCITRAL Model Law. They also include grounds specific to Turkish law, such as an award made after the arbitration period has expired.

Language, tribunal and time. Arbitration seated in Türkiye may be conducted in Turkish or in the official language of a state recognised by Türkiye, so English is available. Under the MTUK, the number of arbitrators must be odd.

Unless the parties agree otherwise, a tribunal under the MTUK must decide the merits within one year from the appointment of a sole arbitrator or from the minutes of the first meeting of a multi-member tribunal. The period may be extended by agreement or, failing agreement, by the court on a party's application; if the application is rejected, the proceedings end when the period expires. Because an award made out of time can be annulled, parties choosing an Istanbul seat should make sure that their agreement, including any institutional rules, deals with the time limit.

6. The institution is a separate decision from the seat

Naming the seat and naming the institution are separate decisions.

The Istanbul Arbitration Centre (ISTAC) was established by Law No. 6570 of 2014 and administers both domestic and international arbitration. Under the ISTAC Arbitration Rules, the seat is Istanbul unless the parties agree otherwise. The Rules include emergency arbitrator provisions and fast-track rules for disputes below a monetary threshold set in the Rules. ISTAC's model clause lists the seat as an optional addition; in a Türkiye–UK contract it should be stated.

Under the LCIA Arbitration Rules 2020, the seat is London in the absence of agreement, unless the tribunal orders otherwise. Article 16.4 provides that the law applicable to the arbitration agreement is the law of the seat unless the parties have agreed in writing on another law. Under the ICC Arbitration Rules 2026, which apply to arbitrations commenced on or after 1 June 2026, the ICC Court fixes the place of arbitration if the parties have not agreed it.

These defaults mean that a clause naming an institution without a seat is not empty. It may, however, produce a seat the parties never considered, with a supervisory court and an annulment regime they did not choose.

Combining an institution with a seat in the other country is possible. ICC or LCIA arbitration can be seated in Istanbul, and ISTAC arbitration can be seated in London. Each combination should be checked for the way the institutional rules interact with the mandatory law of the seat.

Institution names must also be precise. The ISTAC Rules treat references to "ITM", "ISTAC" or similar terms as a choice of the ISTAC Rules. A misdescribed or non-existent institution elsewhere invites an argument that the clause cannot be performed.

Confidentiality is another point on which the seat and the rules matter. English law implies a duty of confidentiality into arbitration agreements, as the Court of Appeal confirmed in Emmott v Michael Wilson & Partners. The 2025 Act did not codify that duty. The MTUK contains no general confidentiality provision. The ISTAC Rules provide that proceedings are confidential unless the parties agree otherwise, the LCIA Rules contain a confidentiality undertaking, and the ICC Rules 2026 bind the arbitrators to confidentiality but impose no default duty on the parties, leaving that to agreement or to orders of the tribunal. Where confidentiality matters commercially, the clause should provide for it expressly.

7. Cost and time depend more on the fee model than on the city

Cost and duration are usually the first practical questions in the choice between Istanbul and London. The three institutions charge in different ways, and each publishes figures on how long its cases take.

• ISTAC: administrative costs and arbitrators' fees follow a scale based on the amount in dispute, set in Turkish lira, and the arbitrators' fees are fixed by the ISTAC Board rather than agreed with the parties. Under the ISTAC Rules, the award is due within six months of the terms of reference, subject to extension, and under the fast-track rules within three months of the file reaching the sole arbitrator. ISTAC reports that 82% of its 2025 cases under the normal procedure concluded within six months to a year, and 86% of fast-track cases within three months.
• LCIA: fees do not depend on the amount in dispute. Arbitrators charge by the hour, normally at rates between £250 and £650 under the LCIA Schedule of Arbitration Costs (2023), and the LCIA adds a registration fee, hourly administrative charges and 5% of the tribunal's fees. The LCIA's 2024 analysis of cases that ended with a final award between 2017 and May 2024 found a median of US$117,653 for tribunal fees and LCIA charges combined, and a median duration of 20 months.
• ICC: administrative expenses and arbitrators' fees are calculated on an ad valorem scale set out in the Schedule of Fees introduced by the ICC Arbitration Rules 2026. For cases that ended with a final award in 2025, the ICC reports an average duration of 27 months and a median of 23 months. The expedited procedure, which applies automatically to disputes up to US$4 million under arbitration agreements concluded on or after 1 June 2026, targets a final award within six months of the case management conference.

These figures are not directly comparable. The institutions measure duration in different ways, most of ISTAC's caseload is domestic, and the LCIA and ICC figures reflect larger disputes, with a median amount in dispute of about US$4.6 million at the LCIA and US$5 million in new ICC cases. None of them includes the largest item in most budgets: the parties' own legal costs.

Whether those legal costs can be recovered from the losing party is where the seat makes a real difference. Under section 61 of the Arbitration Act 1996, costs follow the event unless the tribunal considers that inappropriate or the parties agree otherwise, and section 63 allows a reasonable amount for costs reasonably incurred. Under Article 16 of the MTUK, the losing party also bears the costs unless otherwise agreed, but the counsel fee included in those costs is the amount the tribunal assesses under the Turkish minimum attorney fee tariff, which is usually far below the fees actually incurred. Institutional rules can change that position: the ISTAC Rules, for example, include the parties' costs of legal representation in the costs of arbitration. Parties who expect full cost recovery in an Istanbul arbitration should provide for it expressly.

Enforcement adds its own cost and time. Wherever the seat, enforcing against assets in Türkiye involves Turkish court and enforcement office charges, and an annulment action against an Istanbul award suspends enforcement until it is resolved.

8. In Türkiye, clauses fail on clarity, form, authority or subject matter

Turkish courts examine whether the parties' intention to arbitrate is clear and definite. Several recurring drafting problems put that requirement at risk.

Alternative forums. A clause stating that disputes "may be resolved by arbitration or by the courts" leaves open whether the parties agreed to arbitrate at all. The Assembly of Civil Chambers of the Court of Cassation (Yargıtay Hukuk Genel Kurulu) treats arbitration as an exceptional route that requires an intention clear enough to leave no doubt. In a decision of 1 October 2025 (E. 2024/653, K. 2025/584), it held that wording which accepts arbitration but also gives jurisdiction to the courts does not establish arbitration as the agreed method. If one party is intended to have an option, the mechanism should be drafted with particular care and tested against Turkish law before signature.

Conflicting jurisdiction clauses. Turkish contracts often end with a standard clause conferring jurisdiction on the courts and enforcement offices of a particular city. If that clause sits alongside an arbitration clause without explanation, the contract contains two inconsistent forum choices. In a decision of 15 April 2026 (E. 2025/6-382, K. 2026/262), the Assembly of Civil Chambers considered a construction contract that referred disputes to a four-member arbitral panel and also gave the Istanbul courts and enforcement offices jurisdiction over disputes not settled amicably. It held that the clause did not express a clear and unconditional intention to arbitrate, and that the even number of arbitrators also breached the requirement in Article 415 of the HMK that the number be odd. The court clause should be deleted or expressly confined to interim measures and the enforcement of the award.

Form and incorporation. Both the MTUK and the HMK require written form. That requirement can be met in three ways: by a document signed by the parties; by communications exchanged between them, including by electronic means; or where the defendant, in its statement of defence, does not dispute a written arbitration agreement relied on in the statement of claim. A reference to another document containing an arbitration clause is effective where the reference is intended to make that clause part of the contract.

Standard terms. Where an arbitration clause appears in pre-formulated terms prepared by one party for repeated use, Articles 20 to 25 of the Turkish Code of Obligations No. 6098 (TBK) may be invoked. Under Article 21, standard terms against the other party's interest become part of the contract only if that party was expressly informed of them, had the opportunity to learn their content and accepted them. Article 20 adds that a statement that each term was negotiated does not by itself change their character. A clause that was actually negotiated and is visible in the signed document leaves less room for this argument.

Authority to sign. Under Article 504(3) of the TBK, an agent may not refer a matter to arbitration without special authority. Article 74 of the HMK requires express authority for a lawyer to conclude an arbitration agreement. For a Turkish company, the signatory circular and any power of attorney used for signing should be checked.

Arbitrability. Under Article 408 of the HMK, disputes concerning rights in rem over immovable property and disputes not subject to the parties' free disposal are not arbitrable. Article 1 of the MTUK likewise excludes disputes over rights in rem in immovable property in Türkiye and disputes not subject to the parties' free disposal. An award on such a matter faces refusal of enforcement in Türkiye under Article 62(1)(c) of the MÖHUK.

Foreign element. The MTUK governs arbitration seated in Türkiye where the dispute has a foreign element, and Article 2 defines that element broadly. Any one of the following is sufficient:

• the parties are located in different states;
• a substantial part of the obligations is to be performed, or the dispute is most closely connected with a place, in a state other than the one in which the parties are located;
• a shareholder of a company that is party to the contract brought in foreign capital under the foreign investment legislation, or performance of the contract requires loan or security agreements to raise capital from abroad; or
• the contract moves capital or goods from one country to another.

A Turkish subsidiary of a UK group may therefore fall within the international regime even when contracting with a Turkish counterparty. Where no foreign element exists, the domestic arbitration rules of the HMK apply instead.

9. A Turkish court applies the clause only if it is invoked in time

A valid clause does not stop a counterparty from filing a lawsuit in Türkiye. The respondent has to invoke the clause.

Under Article 5 of the MTUK, the arbitration objection is governed by the HMK rules on preliminary objections. Article 116 of the HMK lists the arbitration objection among the preliminary objections, and Article 117 requires all preliminary objections to be raised in the statement of defence; otherwise they cannot be heard.

The statement of defence is generally due two weeks after service of the statement of claim. The court may grant a single extension, but only on an application made within that period. For a foreign respondent, that timetable leaves little room to instruct Turkish counsel, gather the contract documents and prepare the objection.

If the objection is raised in time, the court upholds it unless the arbitration agreement is null and void, inoperative or incapable of being performed. It then dismisses the claim on procedural grounds.

Article 1 of the MTUK applies Articles 5 and 6 even when the seat is outside Türkiye. A UK party sued in Türkiye under a contract with a London seat must therefore raise the objection in its statement of defence. Missing that point can leave the dispute in the Turkish courts despite the clause.

10. Interim relief has to be planned where the assets are

An arbitration clause does not remove the need for urgent court measures, particularly where assets can be moved.

Under Article 6 of the MTUK, applying to a court for an interim injunction or a precautionary attachment before or during the arbitration does not breach the arbitration agreement. Because of Article 1, this also applies where the seat is outside Türkiye. A party to a London-seated arbitration can therefore apply to the competent Turkish court for measures against assets in Türkiye.

For an international arbitration seated in Türkiye, a party that obtains such a measure from a court must commence the arbitration within 30 days, failing which the measure lapses automatically. Where the seat is abroad, the deadlines under the general Turkish procedural and enforcement legislation should be checked as soon as the order is made.

A tribunal seated in Türkiye may also order interim measures. Under Article 6 of the MTUK, however, it cannot order measures that require execution by enforcement offices or other official authorities, or measures binding third parties.

In England, section 44 of the 1996 Act allows the court, in cases of urgency, to make orders preserving evidence or assets in support of the arbitration. The 2025 Act confirmed that those powers may be exercised in relation to a party or any other person.

The 2025 Act also inserted section 41A. Where an emergency arbitrator appointed under institutional rules makes an order and a party fails without sufficient cause to comply, the emergency arbitrator may make a peremptory order. The court can enforce that order under section 42.

An emergency arbitrator's order made in London is unlikely to be treated as an enforceable foreign arbitral award in Türkiye. The MÖHUK enforcement provisions are directed at awards that are final and enforceable or binding on the parties. For assets in Türkiye, the practical route is usually a direct application to the Turkish court. Our article on cross-border fraud, asset tracing and freezing strategy discusses how these tools are coordinated between jurisdictions.

11. Arbitrators must disclose conflicts in both systems

Section 23A of the Arbitration Act 1996, inserted by the 2025 Act, codifies the duty of disclosure recognised by the Supreme Court in Halliburton v Chubb. Arbitrators, and individuals approached about a possible appointment, must disclose circumstances that might reasonably give rise to justifiable doubts as to their impartiality, including those of which they ought reasonably to be aware.

Article 7 of the MTUK imposes a comparable duty in international arbitration seated in Türkiye, and a challenge must generally be made within 30 days of learning of the ground. In Türkiye–UK disputes, repeat appointments, links with law firms in both jurisdictions and relationships with funders deserve particular scrutiny. Funding is discussed in our guide to third-party funding in international arbitration.

12. Summary awards and narrower challenges change London tactics

Unless the parties agree otherwise, a tribunal seated in England may now decide a claim, defence or issue on a summary basis where there is no real prospect of success (section 39A). The ICC Arbitration Rules 2026 provide a comparable early determination procedure.

Challenges to jurisdiction have also been narrowed. The court will not decide a preliminary question of jurisdiction on which the tribunal has already ruled (section 32), and under amended section 67 it may set an award aside only if remitting it to the tribunal would be inappropriate. Rules of court may now prevent a party that took part in the arbitration from raising new grounds or evidence, or obtaining a rehearing, subject to limited exceptions. The 28-day time limit for challenges runs from the applicable date, which takes account of any arbitral review or material correction.

For a Turkish respondent, the practical consequence is that jurisdictional objections to a London arbitration should be developed in full before the tribunal.

13. Pre-arbitration steps need a fixed end point

Many Türkiye–UK contracts require negotiation or mediation before arbitration, particularly in long-term supply, energy and construction and infrastructure projects.

In Emirates Trading Agency v Prime Mineral Exports, the Commercial Court enforced a time-limited obligation to seek to resolve disputes by friendly discussions. In Republic of Sierra Leone v SL Mining, the Commercial Court held that non-compliance with a pre-arbitration step went to the admissibility of the claim. That was a matter for the tribunal and did not affect its jurisdiction under section 67.

A party should not assume that a Turkish court would analyse the same clause in the same way. Escalation steps work best when they have a fixed duration, a clear starting point and an express statement of what happens if the period ends without settlement. Open-ended wording, such as an obligation to negotiate in good faith until agreement is reached, tends to generate disputes about the dispute clause itself.

14. Existing contracts are read under the new rule

Because section 6A applies to arbitration agreements whenever made, existing Türkiye–UK contracts should be reviewed, particularly those combining a London seat with a main contract governed by Turkish law.

The review should ask:

• whether the clause identifies a seat, or only a city that might be read as a hearing venue;
• whether it states a law for the arbitration agreement itself;
• whether it conflicts with a court jurisdiction clause elsewhere in the contract;
• whether related contracts, such as guarantees, share purchase agreements and side letters, contain compatible dispute clauses;
• whether the person who signed for the Turkish entity had authority to agree to arbitration; and
• whether any Turkish-language version translates the clause consistently, and which language prevails.

Where the answers are uncertain, a short amendment or side letter signed before a dispute arises usually costs far less than litigating the clause later.

15. A clause that works in both systems

A workable arbitration clause for a Türkiye–UK contract usually addresses the following points:

• Scope: disputes arising out of or in connection with the contract, including questions of its existence, validity and termination and non-contractual claims.
• Seat: a city and country expressly designated as the seat, and not only as the venue.
• Institution and rules: the exact name of the institution and of its rules.
• Law of the arbitration agreement: stated expressly, separately from the law of the main contract.
• Tribunal: one or three arbitrators, and the appointment mechanism.
• Language: the language of the arbitration and, for bilingual contracts, which version prevails.
• Time limit: for an Istanbul seat, the period for the final award and how it may be extended.
• Confidentiality: an express obligation where the seat or the rules do not provide one.
• Costs: whether the parties' reasonable legal costs are recoverable, particularly for an Istanbul seat.
• Court support: confirmation that applications to courts for interim measures in Türkiye, England or elsewhere remain available.
• Procedural options: whether emergency arbitrator provisions and summary determination should apply, be excluded or be adjusted.
• Related contracts: consistent clauses in guarantees and ancillary agreements, so that joinder or consolidation is possible where the rules allow it.
• Consistency: deletion or narrowing of any conflicting court jurisdiction clause.

By way of illustration only, the core of a London-seated clause addressing these points might read:

All disputes arising out of or in connection with this Agreement, including any question regarding its existence, validity, interpretation, performance or termination and any non-contractual dispute, shall be finally resolved by arbitration under the [name of the arbitration rules] in force on the date on which the arbitration is commenced. The seat of the arbitration shall be London, England. The tribunal shall consist of three arbitrators. The language of the arbitration shall be English. This arbitration agreement, including its existence, validity and scope, shall be governed by English law. Nothing in this clause shall prevent a party from applying to a competent court for interim or conservatory measures.

Wording of this kind has to be adapted to the institution, the transaction and the place of likely enforcement. For an Istanbul seat, the time limit for the award and the recovery of legal costs should be addressed, and confidentiality should be added where the chosen rules do not provide for it.

The same points arise in technology contracts, discussed in our article on AI-related disputes and arbitration clauses. They also arise in insurance and reinsurance programmes, where London arbitration clauses are common, as discussed in our article on Türkiye–London reinsurance disputes.

Conclusion

The arbitration clause is the part of a Türkiye–UK contract that is used only when the commercial relationship has broken down. At that point, it must work in at least two legal systems at once.

Since 1 August 2025, English law has looked first to an express choice of law for the clause and then to the law of the seat. Turkish law already applied a similar structure to international arbitration seated in Türkiye. Turkish enforcement rules, for their part, look to the law of the country where the award was made when the parties have not chosen otherwise.

That convergence is useful, but it is incomplete, and it does not remove the need for precise drafting. The seat, the institution, the law of the clause, the treatment of court jurisdiction and the authority of the signatory should all be settled at the drafting stage, with the place of eventual enforcement in mind.

For contracts already signed, the question is whether the clause will still produce the outcome the parties expected. Reviewing it now costs less than a jurisdiction dispute later.

How Terziolu & Partners Can Assist

Terziolu & Partners advises on Turkish-law and cross-border dispute resolution, including the drafting and review of arbitration clauses in Türkiye–UK contracts, arbitration objections before Turkish courts, interim measures against assets in Türkiye and the enforcement of foreign arbitral awards in Türkiye.

For transactions and long-term commercial relationships between the two countries, our international business and investment work treats the dispute clause as part of the wider contract structure, alongside the questions covered in our guide to Türkiye–UK market entry.

Where English law, a London seat or English court proceedings are involved, the strategy can be coordinated between Istanbul and London through cross-border legal coordination with appropriately qualified counsel in the relevant jurisdiction. Contact us to review an existing arbitration clause or to discuss the dispute resolution provisions of a new contract.

Selected Legislation, Authorities and Materials

Türkiye

International Arbitration Law No. 4686: Article 1 (scope, including application of Articles 5 and 6 where the seat is abroad), Article 2 (foreign element), Article 4 (form and law of the arbitration agreement), Article 5 (arbitration objection), Article 6 (interim measures), Article 7 (number, disclosure and challenge of arbitrators), Article 10 (commencement, time limit and language), Article 15 (annulment and enforceability) and Article 16 (fees and costs).

Code of Civil Procedure No. 6100: Article 74 (special authority of counsel), Articles 116 and 117 (preliminary objections), Articles 127 and 317 (time for the statement of defence), Article 408 (arbitrability), Article 412 (arbitration agreement), Article 413 (arbitration objection) and Article 415 (odd number of arbitrators).

Court of Cassation, Assembly of Civil Chambers (Yargıtay Hukuk Genel Kurulu), 1 October 2025, E. 2024/653, K. 2025/584: an arbitration agreement requires an intention clear enough to leave no doubt, and wording that also confers jurisdiction on the courts does not suffice.

Court of Cassation, Assembly of Civil Chambers (Yargıtay Hukuk Genel Kurulu), 15 April 2026, E. 2025/6-382, K. 2026/262: a clause providing for arbitration and, otherwise, the Istanbul courts and enforcement offices is invalid; an even number of arbitrators breaches Article 415 of the HMK.

Law No. 5718 on International Private and Procedural Law: Article 57 (execution and appeal), Articles 60 to 62 (competent court, application and grounds for refusing enforcement of foreign arbitral awards) and Article 63 (recognition).

Turkish Code of Obligations No. 6098: Articles 20 to 25 (standard terms) and Article 504 (scope of an agent's authority).

Istanbul Arbitration Centre Law No. 6570: establishment and functions of ISTAC.

ISTAC Arbitration and Mediation Rules: default seat, confidentiality, emergency arbitrator and fast-track arbitration.

ISTAC Model Arbitration Clause: model clause and optional additions on seat, language, number of arbitrators and applicable law.

United Kingdom

Arbitration Act 2025: section 1 (new section 6A), section 2 (duty of disclosure), sections 3 and 4 (arbitrator immunity), sections 5 to 12 (jurisdiction, costs, summary awards, emergency arbitrators, court powers and challenges) and section 17 (commencement and transitional provision).

Arbitration Act 2025 (Commencement) Regulations 2025, SI 2025/905: commencement on 1 August 2025.

Arbitration Act 1996: section 7 (separability), section 44 (court powers in support of arbitration), sections 61 and 63 (costs), sections 67 to 70 (challenges and time limits) and sections 100 to 103 (New York Convention awards).

Law Commission, Review of the Arbitration Act 1996: the review that led to the 2025 Act.

Principal English Authorities

Enka Insaat Ve Sanayi AS v OOO Insurance Company Chubb [2020] UKSC 38: the law governing an arbitration agreement before the 2025 Act.

Kabab-Ji SAL (Lebanon) v Kout Food Group (Kuwait) [2021] UKSC 48: a general choice-of-law clause as an indication of the law of the arbitration agreement under the New York Convention test.

Halliburton Co v Chubb Bermuda Insurance Ltd [2020] UKSC 48: arbitrators' impartiality and duty of disclosure.

Emmott v Michael Wilson & Partners Ltd [2008] EWCA Civ 184: the implied duty of confidentiality in English arbitration.

Emirates Trading Agency LLC v Prime Mineral Exports Private Ltd [2014] EWHC 2104 (Comm): enforceability of a time-limited obligation to negotiate before arbitration.

Republic of Sierra Leone v SL Mining Ltd [2021] EWHC 286 (Comm): pre-arbitration conditions as a question of admissibility.

International and Institutional Materials

New York Convention, status of Contracting States (UNCITRAL): Türkiye's accession in 1992 and its declarations.

LCIA Arbitration Rules 2020: Article 9B (emergency arbitrator), Article 16 (seat and law of the arbitration agreement) and Article 30 (confidentiality).

ICC Arbitration Rules 2026: Article 12(8) (arbitrators' confidentiality), Article 19 (place of arbitration), Article 30 (early determination), the expedited procedure and the Schedule of Fees, in force from 1 June 2026.

ICC Dispute Resolution 2025 Statistics: duration of ICC arbitrations ending with a final award in 2025.

LCIA Schedule of Arbitration Costs (2023): registration fee, administrative charges and arbitrators' hourly rates.

LCIA Costs and Duration Analysis 2024: median costs and duration of LCIA arbitrations with final awards from 2017 to 2024.

ISTAC 2025 Statistics: caseload and duration of ISTAC arbitrations in 2025.