The sixth HMS Bulwark of the Royal Navy was a 22,000 ton Centaur-class light fleet aircraft carrier. Initially commissioned as a light aircraft carrier in 1954, the ship was converted into a commando carrier in 1958 and recommissioned as such in 1960. Bulwark remained in this capacity until 1979 following failed efforts to sell the ship, Bulwark re-entered service as an anti-submarine warfare carrier and remained as such until being decommissioned in 1981. The ship was scrapped in 1984.

Bulwark was laid down by the Harland & Wolff shipyard in Belfast on 10 May 1945. She was launched on 22 June 1948, but was not commissioned into the Royal Navy until 4 November 1954.

In 1956, Bulwark took part in her first combat operation, during the Suez Crisis, when she launched up to 600 sorties during Operation Musketeer. On 13 September 1958, Bulwark was exercising with the frigate Loch Killisport in the Gulf of Oman when the tankers SS Melika and Fernand Gilabe collided in the Persian Gulf and caught fire, the tankers' crews abandoning ship. Bulwark went to the aid of the two blazing tankers, with her helicopters landing fire fighting parties onto the tankers. Bulwark, with the aid of the frigate Puma, towed Melika, to Muscat. Bulwark's Whirlwind helicopter squadron, 845 Naval Air Squadron, was awarded the Boyd Trophy for the squadron's role in the rescue.

The final fixed wing complement, as embarked in 1957 (the Gannet squadron was dropped in 1958), was as follows:

In 1958 she paid off at Portsmouth for conversion into a commando carrier. Her sister ship, Albion, did likewise in 1961.

In 1960, Bulwark was recommissioned with 42 Commando Royal Marines and 848 Squadron attached to the carrier. In 1961, due to an increasing threat of invasion of Kuwait by Iraq, Bulwark landed 42 Commando in Kuwait. In the same year, she became the first Royal Navy warship since the Second World War to commission outside the UK, commissioning instead in Singapore. She also took part in the campaign against Indonesia, during the Indonesian Confrontation. In June 1966 she carried out sea trials with the Kestrel: the forerunner of the Harrier fighter aircraft made famous during the Falklands War.

In 1967, she again commissioned in Singapore Naval Dockyard (HMS Sembawang), and following her work up, proceeded to Aden to cover the withdrawal and relieve Albion. By this time, Bulwark's nickname "The Rusty B" had become firmly established.

In 1968, after service in the Arctic with 45 Commando embarked for Exercise Polar Express, the ship spent some time in dry dock in Portsmouth Dockyard for a refit. For the duration of the refit, the ship's company was accommodated in Centaur.