The largest Royal Navy fleet yet assembled in the Mediterranean set out from Gibraltar on the 30th August 1940. Force H led by Admiral Somerville was attempting to provoke the Italian fleet into battle, whilst supporting the escort of a convoy to Malta.
‘Operation Hats’ consisted of the aircraft carriers HMS Ark Royal and HMS Illustrious with the battle cruiser HMS Renown and the battleship HMS Valiant supported by three cruisers and seventeen destroyers. For the first time the fleet was defended by all round radar, based on four ships covering different sectors. Although the fleet was spotted by Italian aircraft, the Italian Navy did not attempt an engagement.
After joint operations with HMS Ark Royal, in which Swordfish aircraft attacked the Italian airfield at Caglieri, HMS Illustrious and HMS Valiant left the force on 2nd September to join the Mediterranean fleet based at Alexandria.