Marquess of Ailesbury (later styled Aylesbury), in the County of Buckingham, is a title in the Peerage of the United Kingdom.

[4] On Lord Ailesbury's death in 1747, his English titles became extinct, except for the 1746 Barony of Bruce, which was inherited by his nephew, Robert, according to the special remainder.

[5][6] On 10 June 1776 he was created Earl of Ailesbury, in the County of Buckingham, in the Peerage of Great Britain,[7] a revival of the title which had become extinct on his uncle's death 29 years earlier.

[8][9] In 1838 his eldest son, George Brudenell-Bruce, 2nd Marquess of Ailesbury, was summoned to the House of Lords through a writ of acceleration in his father's junior title of Baron Bruce.

In addition, there is a white square in the top left corner of the shield with a blue lion rampant (for the Bruce family); the top right and bottom left quarters are white with a red chevron between three blue caps of state that are turned to face to the viewer's right (for the Brudenell family).

The heir apparent is the present holder's son, Thomas Brudenell-Bruce, Earl of Cardigan (born 1982).