On 2 April 1982, however, Argentina invaded the Falkland Islands. Three days later, a naval task force headed by "Invincible" and "Hermes" left HMNB Portsmouth bound for the South Atlantic. On 20 April, the UK government formally ordered its defence forces to bring the islands back under British control. Along with eight Sea Harriers, the "Invincible"s airgroup included twelve Sea King helicopters that were slightly larger than the ship had originally been designed to accommodate. Small machine guns were added around the flight deck and island for close-in defence.