English Arbitration Act 2025: A New Era for London-seated Arbitration from 1 August 2025 

The UK Government has confirmed that the long-anticipated Arbitration Act 2025 (the '2025 Act') will come into force on 1 August 2025.

The 2025 Act, which introduces a number of amendments to the Arbitration Act 1996 (the '1996 Act'),¹ will apply to arbitration proceedings commenced after 1 August 2025 as well as to court proceedings brought in respect of arbitration proceedings commenced after that date.

The changes introduced in the 2025 Act are significant: they address practical concerns raised by users and practitioners while preserving the pre-existing strengths of the English legislative framework applicable in English-seated arbitration (Scotland has its own legislation). The 2025 Act is intended to reinforce London as a leading global centre for international arbitration against the backdrop of increasing competition from new seats, especially Singapore and long-established seats such as Paris with effective marketing machines.

We set out below six of the reforms that will come into force on 1 August 2025² and which may significantly impact parties arbitrating in London:

(1) Governing law – The 2025 Act establishes a new default rule that the governing law of an arbitration agreement shall be the same as the law of the seat of the arbitration, unless the parties expressly agree otherwise. This means that, unless otherwise agreed, English-seated arbitration agreements – and questions as to their validity and enforceability – will now be governed by English law. This will be particularly significant in agreements where the choice of seat and substantive governing law are not the same and could come as a surprise to parties from other jurisdictions where there is a default rule that the law of the arbitration will follow an express choice of law to govern the main agreement.

(2) Summary disposal – The 2025 Act empowers the arbitral tribunal to issue a summary arbitral award, upon a party's application, where a claim (or defence) has no real prospect of success. This power, however, can be opted out of by the parties' agreement. For arbitration agreements signed prior to the 2025 Act (and agreements signed after the 2025 Act without any such opt-out), this new provision will give parties the ability to bring frivolous or vexatious proceedings to an early end.

(3) Preliminary jurisdictional challenges – Under the 2025 Act, where a tribunal has already decided on its own jurisdiction as a preliminary question, parties are barred from subsequently applying to the court on the same issue.³ This should prevent respondents from using preliminary jurisdictional challenges before the courts to delay tribunals from proceeding to deal with the merits.

(4) Challenges to awards on jurisdictional grounds – The 2025 Act envisages new court rules being introduced to prevent parties from adducing evidence and submissions in set aside proceedings based on alleged lack of jurisdiction,⁴ if such evidence and submissions have already been considered by the tribunal. Those rules have not yet been finalised, and it remains to be seen how these provisions of the 2025 Act will take effect in practice.

(5) Emergency arbitrators – The 2025 Act confers on emergency arbitrators the power to issue peremptory orders, which can result in court-ordered enforcement, and to grant permission for applications to the court for a section 44 interim relief.⁵ The 2025 Act also confirms that the interim relief granted under section 44 of the 1996 Act, including order for the preservation of evidence, is available against third parties. It remains to be seen whether these provisions will result in an increased amount of arbitration-related court applications.

(6) Duty of disclosure – The duty of disclosure for arbitrators, based on English common law and now codified by the 2025 Act, is based on what an arbitrator 'ought reasonably' to know that might give rise to justifiable doubts about their impartiality. This provision might result in broader disclosures from arbitrators, and greater scope for recalcitrant parties to seek to challenge arbitrators, if only as a means of causing delay.

After 1 August 2025, London-seated arbitration will have one of the most up-to-date procedural laws governing international arbitration globally. It remains to be seen whether the marketing and promotional energy displayed by competitor seats can now be matched.