This Practice Note considers state immunity and arbitration issues under UK law, specifically under the provisions of the State Immunity Act 1978 (SIA 1978). It considers what state immunity is (sometimes referred to as sovereign immunity), the general rule on state immunity, the exceptions to the general rule on state immunity including submission to the jurisdiction of the English courts (voluntary and deemed submission to jurisdiction), submission or agreement to arbitration by a state (the arbitration exception; SIA 1978, s 9), commercial transactions and contracts to be performed in the UK, the meaning of ‘state’ and ‘separate entities’ for the purposes of state immunity; the special rules for injunctions against a state and for execution against property of a state; service of arbitration claim forms and enforcement proceedings on states; and, non-justiciability or act of state. A link to our Practice Note on state immunity and arbitration generally is also available. This topic may also be referred to as: foreign state immunity and international arbitration; state immunity under English law; and, state or sovereign immunity and enforcement of arbitral awards.