The ship was originally ordered from the Smiths Dock Company of South Bank, Middlesbrough on 25 January 1943 as the Loch Carron. However the contract was changed in 1944, and the ship was laid down as Admiralty Job No J4788 on 21 April 1944 to a revised design as a Bay-class anti-aircraft frigate. She was launched on 14 March 1945 as Gerrans Bay, but after the end of the war the plans were changed again and the ship was converted to a Despatch Vessel for use by the Commander-in-Chief, Mediterranean Fleet. The aft twin 4inches gun mounting was removed and replaced by offices and accommodation for the CinC and his staff. The ship was completed on 7 September 1946 and renamed Surprise with the pennant number K346.[1]
After sea trials Surprise was commissioned in September 1946, and sailed to Valletta, Malta, where she remained with the ships of the Mediterranean Fleet for exercises and visits throughout the Mediterranean Sea and the Red Sea, with periodic refits at HM Dockyard, Valletta.[1]
In November 1952 Surprise returned to Portsmouth. As the Royal Yacht was still under construction Surprise was selected for conversion for use by Queen Elizabeth II in the Coronation Review. The forward twin 4 inch mounting was replaced by a special viewing platform. The work was completed in March 1953, and after trials in the English Channel, the ship was deployed at Portsmouth. She then sailed to the Solent and took part in the Fleet Review by Queen Elizabeth II on 15 June 1953.[2] All members of ship's company were subsequently awarded Coronation Medal. The Royal Crest fitted in front of the bridge was retained as a permanent feature to commemorate her service. Surprise returned to Malta in July to resume her previous duties.[1]
In 1961 a decision was made to retain the ship in service as the Flag Frigate as long as possible without a major refit, and the complement was reduced to 80.[1]
In late 1964 Surprise returned to the UK, arriving at Portsmouth on 12 December. In January 1965 she was decommissioned and placed on the Disposal List. She was sold to BISCO on 29 June 1965.[1]