The Invincible class was a class of light aircraft carrier operated by the Royal Navy. Three ships were constructed: HMS Invincible, HMS Illustrious and HMS Ark Royal. The vessels were built as aviation-capable anti-submarine warfare (ASW) platforms to counter the Cold War North Atlantic Soviet submarine threat, and initially embarked Sea Harrier aircraft and Sea King HAS.1 anti-submarine helicopters. With cancellation of the aircraft carriers renewal programme in the 1960s, the three ships became the replacements for the Audacious-class fleet carriers and the Centaur-class light fleet carriers, and the Royal Navy's sole class of aircraft carrier.