Considerable attention has been given in recent years to judicial developments that tend against the particular immunities and privileges enjoyed by sovereigns when it comes to litigation. Notably, a number of courts in different jurisdictions have increasingly narrowed the sovereign immunity arguments available when it comes to execution against state assets.
The public policy questions that frame that debate are well-trodden. States rely on the ancient tradition of sovereigns being immune from the jurisdiction of foreign courts (other than with respect to specific exceptions). Those litigating against states see what appear as greater state involvement in commercial and non-sovereign activities, and favour making it easier to bring suit against a sovereign.
In the United Kingdom, there are perennial discussions on whether to reform the State Immunity Act as it approaches its 50th anniversary. Lord Lloyd-Jones, Justice of the Supreme Court, said in a 2018 speech that as the act entered its ‘middle age…in general, it has stood the test of time reasonably well’. Whether that assessment will hold in the light of the continuing pace of sovereign litigation and immunity issues remains to be seen.
Interestingly, many of the judicial decisions that frame state immunity in the United Kingdom arise in an employment context. A recent such case, involving the Cultural Bureau of the Embassy of the Kingdom of Saudi Arabia, resulted in judgment in September 2025. It provides a clear warning to states as to the further narrowing they can expect in terms of the privileges they enjoy when litigating in this jurisdiction.
The warning is contained in a part of the judgment that did not form part of the ratio of the decision. However, in circumstances where the Court of Appeal was in clear agreement on the point, it can only be a matter of time before it is formalised. The issue is whether or not the decision in Republic of Yemen -v- Aziz [2005] EWCA Civ 745, another diplomatic employment case, is still one the English Court should follow.
In the Aziz case the Republic of Yemen, having lost at first instance, sought to adduce evidence on appeal that the litigation had proceeded without authority. The relevant diplomat had apparently misunderstood the nature of the litigation and the Ambassador indicated that he had not authorised the instruction of solicitors to act. The Court in that case held that a solicitor acting without actual authority of the state could not waive its immunity.
A similar case was run by the Kingdom of Saudi Arabia in Embassy of Saudi Arabia (Cultural Bureau) -v- Alhayali [2025] EWCA Civ 1162. While ultimately the point did not need to be decided, the Court made clear it skepticism towards the reasoning of the Aziz case. In particular, if Aziz was correct, states might ostensibly participate in proceedings until the result seemed likely to be negative, and then adopt the position that the participation in the proceedings was never properly authorised and they thus remained immune. Lord Justice Coulson, in his concurring judgment, emphasised the distinction between actual and deemed submission to the jurisdiction: if the Court’s objective analysis was that the state was participating in a manner to impliedly affirm the proceedings then it would be deemed to have submitted to the jurisdiction of the Court.
There is obvious good sense in the Court guarding carefully against a contradictory approach by sovereign parties in litigation. It would seem perverse for any party to be able to, at the last minute, claim that their solicitors were in fact not acting with authority so as to avail themselves, in the case of states, of an immunity argument. However, states will need to have clearly in mind the increased need for vigilance against litigation and how state agents engage with it at an early stage. If the actual authority of that agent to conduct the litigation will not be relevant, then there is a substantial risk of the state becoming committed to the proceedings on their merits without possibility of correction.
It would seem that the Aziz position will not survive any further direct reliance placed on the arguments that underly that decision. The wider move against the immunities and procedural privileges of states in litigation, is something that may still require wider legislative reform, rather than piecemeal common law development.
Sarah Gabriel (Partner) and Philip Gardner (Senior Associate) have substantia experience acting in sovereign contexts, including with respect to issues arising under the State Immunity Act 1978.
