James Thomas was born in Epsom on 23 December 1918, the son of Edgar William Thomas CBE (a Civil Servant) and Phyllis Annette Thomas (née Whitmore), later of Chelsea, London. At the time of the 1921 census the Thomas family were living at ‘Gurteen’, Highfields, Ashstead, Surrey, and there was also a three year old sister – Celia Thomas.

James Thomas joined the Royal Navy as a Cadet on 1 September 1936. His promotion to Midshipman appears to have been backdated to 1 May 1936. He was promoted to Acting Sub Lieutenant on 1 May 1939 and appointed to the Naval College at Portsmouth on the same date for his ‘G’, ‘T’ & ‘N’ Courses for the Rank of Lieutenant’. Further promotion to Acting Sub Lieutenant followed and, on 1 October 1939, he was appointed to the destroyer HMS ACHATES.

Sub Lieutenant Thomas was appointed to HMS DOLPHIN ‘for the Submarine Course’ on 6 May 1940 and then to the Submarine Base HMS ELFIN at Blyth on 15 June 1940. He was appointed to HMS PORPOISE ‘as the Navigating Officer’ on 9 August 1940. On 25 September 1941 he was serving in the Submarine Depot Ship HMS TITANIA ‘for HMS PORPOISE as First Lieutenant’, working up following a refit. He was then onboard PORPOISE for four North Atlantic war patrols escorting convoys from Halifax, Nova Scotia, to UK, followed by a refit at Troon from May to September 1941.

HMS PORPOISE was next deployed to the Mediterranean via Gibraltar and Malta to join the 1st Submarine Flotilla at Alexandria. James Thomas was onboard for two more war patrols in the Mediterranean and four store carrying patrols from Alexandria to Malta.

On 15 April 1942, HMS PORPOISE arrived back in Alexandria from Malta and, on the same day, James Thomas died in the 64th General Hospital, M.E.F., in Alexandria, from multiple injuries sustained either in a road traffic accident or fall from a train in Alexandria although the circumstances of the accident are unclear. James Thomas, who was unmarried, is buried in the Hadra War Memorial Cemetery in Alexandria, Egypt in Grave 1.D.16.