LOCHINVAR was commissioned in November 1939 as a training school for Minesweeping and the Royal Naval Patrol Service, at Port Edgar on the south shore of the Firth of Forth adjacent to the famous Forth Rail Bridge.

In 1962 the task of HMS LOCHINVAR was re-defined to co-ordinate and support the UK Mine Countermeasures Flotilla, namely the 1st Minehunting Squadron, the 2nd Minesweeping Squadron, the Mine Countermeasures Support Ship, (formerly Deep Diving Ship) HMS RECLAIM and also the vessels of the Fishery Protection Squadron.

The Commanding Officer LOCHINVAR became Captain Mine Countermeasures (Home), being responsible for all MCM matters in Home Waters and adviser to Admiralty and Commanders in Chief abroad on these matters.

In the summer of 1963 LOCHINVAR’s MCM ships combined with Vernon, Portland and Fishery protection and five RNR minesweepers to carry out Operations CLEAR ROAD, based on Esbjerg, Denmark, and CABLEWAY, based on Den Helder, Holland. These tasks demanded clearing channels for vessels laying telecommunications cables through wartime minefields; each channel being 48 miles long and two miles wide. Twenty-four ships, plus RECLAIM and LAYMOOR participated .

HMS RECLAIM and ships of the 2nd MSS also cleared wartime minefields in two Icelandic fjords during September 1963. This is believed to be the first time that coastal minesweepers had ventured north of the Arctic Circle.