He is best known for his part as commander of Task Force 308 in Operation Mosaic, the series of British nuclear tests in the Monte Bello Islands in Western Australia in 1956.

[4] In 1937, he posted to HMS Excellent, on Whale Island near Portsmouth, where he qualified as a gunnery officer.

He participated in the Dunkirk evacuation and then joined the cruiser HMS Berwick, on which he served in the Arctic convoys.

In 1956 he was appointed to command Task Force 308, which conducted the Operation Mosaic series of British nuclear tests in the Monte Bello Islands in Western Australia, with the temporary rank of commodore, flying his pennant on the Landing Ship, Tank, HMS Narvik.

[12] Martell attended the Imperial Defence College at Seaford House, Belgrave Square, and returned to HMS Excellent, this time as its commander.

He became the Director of Tactical and Weapons Policy in 1959,[1] and as a naval aide-de-camp to Queen Elizabeth II on 7 January 1961.

He hoisted his flag on the retiring cruiser HMS Belfast, manned it with a mixed crew of former RNR and RNVR, and sailed it and a small force of coastal minesweepers to Gibraltar for two weeks' intensive training.

[18] In retirement, he worked for the defence electronics firm Racal, and headed the European operations of Penthouse.