[3] Following the inter-war period, a Fleet Requirements Unit, 772 Squadron, arrived at Portland in September 1939 and stayed until July 1940.

As a result, HMS Osprey was moved to Cambeltown in July 1940, taking 772 Squadron with it, and leaving Portland's base to remain under Care and Maintenance.

[1] After the war HMS Osprey returned to Portland and a helicopter base became an important centre for the school to perform experiments and development.

In 1946 Sikorsky R-4Bs moved in and the success of their trials at Portland led the Admiralty to replace fixed-wing aircraft with helicopters for use in the fleet.

[2] During the late 1950s the marshy area known as the Mere was filled in and built over, and later expansion meant that this tidal lagoon was completely covered.

[3] Upon the completion of the work, 815 Naval Air Squadron flew its 12 Westland Whirlwinds to the new Portland Heliport on 14 April 1959.

[1][2] With the reduction of armed forces, Portland's naval base closed on 29 March 1996, with the Flag Officer Sea Training (FOST) moving to Plymouth's (HMS Drake).