The right of veto vested in the sovereign by this Act provoked severe adverse criticism at the time of its passage.

Royal assent was given to the Act on 1 April 1772,[6] and it was only on 13 September following that the king learned that another brother, Prince William Henry, Duke of Gloucester and Edinburgh, had in 1766 secretly married Maria, the illegitimate daughter of Sir Edward Walpole and the widow of the 2nd Earl Waldegrave.

It had been claimed that the marriage of Prince Augustus had been legal in Ireland and Hanover, but the Committee of Privileges of the House of Lords ruled (in the Sussex Peerage Case, 9 July 1844) that the Act incapacitated the descendants of George II from contracting a legal marriage without the consent of the Crown, either within the British dominions or elsewhere.

All European monarchies, and many non-European realms, have laws or traditions requiring prior approval of the monarch for members of the reigning dynasty to marry.

But Britain's was unusual because it was never modified between its original enactment and its repeal 243 years later, so that its ambit grew rather wide, affecting not only the British royal family, but more distant relatives of the monarch.

This would also mean theoretically, for example, that the present royal family of Norway was bound by the Act, for the marriage of Princess Maud, a daughter of King Edward VII, to the future King Haakon VII of Norway, was a marriage to a "British subject", since Haakon descended from the Electress Sophia.

[19] In October 2011 David Cameron wrote to the leaders of the other Commonwealth realms proposing that the Act be limited to the first six people in line to the throne.

[20] The leaders approved the proposed change at the Commonwealth Heads of Government Meeting held in Perth, Western Australia.

Not all consents were there and gaps in the list have been filled by reference to the Warrants for Royal Marriages in the Home Office papers (series HO 124) in The National Archives:[23]