She was built to support the increasing number of submarines, especially on distant stations, such as the Mediterranean Sea and the Pacific Far East.

Besides large workshops, there were repair facilities for all materiel in the attached submarines and extensive diving and salvage equipment was carried.

There were steam laundries, a cinema, hospital, chapel, two canteens, a bakery, barber shop, and a fully equipped operating theatre and dental surgery.

In September 1944 Maidstone and the 8th Submarine Flotilla were transferred from Ceylon to Fremantle in Western Australia to operate in the Pacific.

[2] On 16 June 1955 the submarine HMS Sidon sank in Portland harbour alongside Maidstone 20 minutes after an explosion in the forward torpedo compartment.

In September 1957, the Soviet Union protested when Maidstone accompanied the training aircraft carrier HMS Ocean on a visit to Helsinki.

She also undertook a trip to Rothesay during this period and then, in 1968, she sailed to Rosyth Dockyard to undertake preparations to permanently retire it.

She was moored in the Herdman Channel in Belfast harbour, 20 feet (6.1 m) from the land, entry to the jetty being guarded by sand-bagged army emplacements.

[9] The presence of the ship in Belfast Harbour drew attention to the constitutional status of Northern Ireland's territorial waters, which had long been a point of contention with the Irish government.

[10] By early 1975 the ship remained at Sydenham Wharf in Belfast as part of the Royal Naval Operation in Northern Ireland, to provide immediate short-notice accommodation for the Army, should significant reinforcements be required and to provide ad-hoc accommodation for UK Service Personnel visiting the Province.