Admiral of the Fleet John Forbes, styled The Honourable from 1734, was a Royal Navy officer. After taking part in an expedition to Lisbon to support the Portuguese in the face of a Spanish threat, he saw action as captain of the third-rate HMS Norfolk at the Battle of Toulon during the War of the Austrian Succession. He was one of the few captains who really bore down on the enemy.

Admiral of the Fleet is a five-star naval officer rank and the highest rank of the Royal Navy, formally established in 1688. The five-star NATO rank code is OF-10, equivalent to a field marshal in the British Army or a Marshal of the Royal Air Force. Apart from honorary appointments, no new admirals of the fleet have been named since 1995, and no honorary appointments have been made since 2014.