PART III Miscellaneous and Supplementary

20 Heads of State
(1) Subject to the provisions of this section and to any necessary modifications, the Diplomatic Privileges Act 1964 shall apply to—
(a) a sovereign or other head of State;
(b) members of his family forming part of his household; and
(c) his private servants,
as it applies to the head of a diplomatic mission, to members of his family forming part of his household and to his private servants.
1964 c. 81.
(2) The immunities and privileges conferred by virtue of subsection (1)(a) and (b) above shall not be subject to the restrictions by reference to nationality or residence mentioned in Article 37(1) or 38 in Schedule 1 to the said Act of 1964.
(3) Subject to any direction to the contrary by the Secretary of State, a person on whom immunities and privileges are conferred by virtue of subsection (1) above shall be entitled to the exemption conferred by section 8(3) of the Immigration Act 1971.
1971 c. 77.
(4) Except as respects value added tax and duties of customs or excise, this section does not affect any question whether a person is exempt from, or immune as respects proceedings relating to, taxation.
(5) This section applies to the sovereign or other head of any State on which immunities and privileges are conferred by Part I of this Act and is without prejudice to the application of that Part to any such sovereign or head of State in his public capacity.

21 Evidence by certificate
A certificate by or on behalf of the Secretary of State shall be conclusive evidence on any question—
(a) whether any country is a State for the purposes of Part I of this Act, whether any territory is a constituent territory of a federal State for those purposes or as to the person or persons to be regarded for those purposes as the head or government of a State;
(b) whether a State is a party to the Brussels Convention mentioned in Part I of this Act;
(c) whether a State is a party to the European Convention on State Immunity, whether it has made a declaration under Article 24 of that Convention or as to the territories in respect of which the United Kingdom or any other State is a party ;
(d) whether, and if so when, a document has been served or received as mentioned in section 12(1) or (5) above.

22 General interpretation
(1) In this Act " court" includes any tribunal or body exercising judicial functions; and references to the courts or law of the United Kingdom include references to the courts or law of any part of the United Kingdom.
(2) In this Act references to entry of appearance and judgments in default of appearance include references to any corresponding procedures.
(3) In this Act "the European Convention on State Immunity " means the Convention of that name signed in Basle on 16th May 1972.
(4) In this Act " dependent territory " means—
(a) any of the Channel Islands;
(b) the Isle of Man;
(c) any colony other than one for whose external relations a country other than the United Kingdom is responsible ; or
(d) any country or territory outside Her Majesty's dominions in which Her Majesty has jurisdiction in right of the government of the United Kingdom.
(5) Any power conferred by this Act to make an Order in Council includes power to vary or revoke a previous Order.

23 Short title, repeals, commencement and extent
(1) This Act may be cited as the State Immunity Act 1978.
(2) Section 13 of the Administration of Justice (Miscellaneous Provisions) Act 1938 and section 7 of the Law Reform (Miscellaneous Provisions) (Scotland) Act 1940 (which become unnecessary in consequence of Part I of this Act) are hereby repealed.
1938 c. 63.
1940 c. 42.
(3) Subject to subsection (4) below, Parts I and II of this Act do not apply to proceedings in respect of matters that occurred before the date of the coming into force of this Act and, in particular—
(a) sections 2(2) and 13(3) do not apply to any prior agreement, and
(b) sections 3, 4 and 9 do not apply to any transaction, contract or arbitration agreement,
entered into before that date.
(4) Section 12 above applies to any proceedings instituted after the coming into force of this Act.
(5) This Act shall come into force on such date as may be specified by an order made by the Lord Chancellor by statutory instrument
(6) This Act extends to Northern Ireland.
(7) Her Majesty may by Order in Council extend any of the provisions of this Act, with or without modification, to any dependent territory.