Admiralty Flag (Lord High Admiral's Flag). It is made of bunting; the fabric is a wool/synthetic blend with the anchor applied in cotton cambric. The flag is machine-sewn, a rope and two Inglefield clips are attached for hoisting. Inscribed on the hoist is 'LORD HIGH ADMIRAL 571-4390 12 BDS'.
This flag was flown by HMY 'Britannia' during Queen Elizabeth II's Silver Jubilee tour in the summer of 1977.

The design originated during the early 17th century as the badge of the Lord High Admiral (a number of variations are recorded). At the Restoration, a horizontal yellow anchor and cable on a red field was accepted as the distinguishing flag of the Lord High Admiral. In practise, the Royal Standard was used as a command flag unless the king himself was present. After 1702, use of the Royal Standard was restricted to the Sovereign. After that the flag was used as a command flag by the Lord High Admiral, or by a ship carrying two or more members of the Board of Admiralty. Since the board’s dissolution in 1964 the flag has been the prerogative of the Sovereign who is also Lord High Admiral. Since the reign of Charles II, the anchor flag was one of three flags used when the Sovereign was on board a British warship. The other two were the Royal Standard and the Union Flag. The same three flags were used in the 18th and 19th centuries at the launch of a naval ship.