HMS Conqueror was a Churchill-class nuclear powered submarine that served in the Royal Navy from 1971 to 1990. She was built by Cammal Laird in Birkenhead. As of 2003, she was the only nuclear powered submarine to have engaged an enemy ship with torpedoes, sinking the cruiser General Belgrano.

Conqueror was the second of the class, the other two being HMS Churchill and HMS Courageous.

The main aim of these submarines was to face the Soviet threat at sea by attacking other ships and submarines, and spying on Soviet nuclear armed submarine movements.

However, Conqueror was most famously deployed during the Falklands War, setting sail from Faslane Naval Base on the River Clyde in Scotland on 3 April 1982, two days after the Argentine invasion. Conqueror arrived in the exclusion zone around the Falklands 21 days later. She was ordered to scan the area for Argentine shipping, particuarly the Argentine aircraft carrier, ARA Vienticinco de Mayo. However, on 30 April, she spotted the Argentine heavy cruiser, ARA General Belgrano. The Belgrano was sailing South West of the Falklands just outside the exclusion zone imposed by the British on Argentine shipping. After the opening shots of the war had occurred, British admiral, Rear Admiral J. F. Woodward, ordered Conqueror to sink the Belgrano. The message was intercepted by Northwood, the Royal Navy's fleet command centre back in the UK. The British government, after some debate, allowed the decision to proceed. The basis for the decision was that the Royal Navy feared a pincer style attack with Belgrano attacking from the South and the Vienticinco de Mayo from the North. Also the Belgrano could have escaped from Conqueror by sailing across shallow waters and attack the British Task Force with its large 405mm guns.

The scene was now set, and on 2 May, Conqueror became the first nuclear powered submarine to fire in anger when she launched three torpedos at the Belgrano, two of which struck the ship and exploded. Twenty minutes later, the ship was sinking rapidly and was abandoned by the crew. The two escorting destroyers fled the scene under fear of further attack. 323 men were killed.

Conqueror's war did not end there. The crew of the submarine had to face Argentine air force attempts to locate the ship in the days after the attack, which had shocked the Argentine people, and the ruling dictatorship. Conqueror did not fire again in anger during the war, but they did provide valuable help to the task force by using their sophisticated monitoring equipment to track Argentine aircraft departing the mainland.

After the war, Conqueror returned to Faslane, flying the Jolly Roger, a customary act of Royal Navy submarines after a "kill".

Conqueror did not take part in any other official conflicts, and was decommisioned in 1990. The periscope of the submarine can be viewed in the Royal Navy's museum in Portsmouth.

Courageous is open to the public at Devonport Dockyard.