HMS Lion was a Tiger-class light cruiser of the British Royal Navy, originally ordered in 1942 as one of the Minotaur class and laid down that same year as Defence by Scotts Shipbuilding and Engineering Company at Greenock in Scotland on 6 June 1942.

Work was stopped and not begun again until the mid-1950s for completion as an air-defence cruiser pending the introduction of guided missile-equipped County-class destroyers into the navy.

Lion was fitted with one hydraulic and one electric powered turret in A and Y positions, The three Mk 24 turrets in A, B and Y would have given more reliable all angle surface cover against multiple targets [3][a] Still named Defence, she was laid up at Gareloch in Scotland for eight years in dehumidified sealed state in the RN Reserve Fleet, while the other incomplete Tigers remained with their builders.

[citation needed] She was finally commissioned in July 1960, having been rushed into service with some shortcuts in the engineering department, due to political pressure to get her to sea.

Initial trials were disrupted by severe rotor, turbine and vibration problems and a further three months in Portsmouth dockyard were required before she became fully operational in February 1961.

Lion recommissioned at Devonport for service in the Home Fleet and Far East on 31 July 1962 and sailed to the Mediterranean for work-up at the end of November.