The 443 ton trawler was laid down on 2 July 1935 at Smiths Dock Company of South Bank-on-Tees and completed by the end of the year.

[2][3] On 17 June 1940, Cambridgeshire took part in the rescue of passengers and crew from the bombing of RMS Lancastria in the estuary of the River Loire during Operation Aerial.

[5] Later that night, Cambridgeshire received orders to evacuate the commander of the British Expeditionary Force, Lieutenant-General Alan Brooke, and his staff to England because the destroyer allocated was no longer available.

[6] There were no rafts or life jackets onboard following the rescue work and the decks were covered in bunker oil and discarded clothing.

[7] She left St Nazaire at 3am on 18 June and arrived in Plymouth late in the afternoon of the following day, having acted as an escort to a convoy of evacuation ships en route.