On 2 May Conqueror  became the first nuclear-powered submarine to fire in anger, launching three torpedoes at the General Belgrano, two of which struck the ship and exploded. Twenty minutes later, the ship was sinking rapidly and was abandoned by her crew. General Belgrano was unable to issue a Mayday signal because of electrical failure; this and poor visibility meant the two escorting destroyers were unaware of the sinking until some hours later.

 A total of 323 Argentinian sailors were killed. 

After the war, Conqueror returned to Faslane, flying the Jolly Roger adorned with torpedoes, a customary act of Royal Navy submarines after a kill. When asked about the incident later, Commander Wreford-Brown responded, "The Royal Navy spent thirteen years preparing me for such an occasion. It would have been regarded as extremely dreary if I had fouled it"