UK Arbitration Act 2025 - An Exception For Treaties

The Arbitration Act 2025 has recently received royal assent, introducing several key changes to the arbitration landscape. See here for the four key reforms relevant to commercial parties.

One of the most notable reforms is the new default rule that, in the absence of an express agreement between the parties on the law governing the arbitration agreement, it is the law of the seat that applies. The Act states that this rule applies even if the seat of the arbitration is outside England and Wales or Northern Ireland or no seat has been designated or determined. An exception to this rule, in Section 6A(3), is that it "does not apply to an arbitration agreement derived from a standing offer to submit disputes to arbitration where the offer is contained in – (a) a treaty, or (b) legislation of a country or territory outside the United Kingdom". The Explanatory Notes (18) explain that: "This means, for example, that non-ICSID [i.e. International Centre for Settlement of