Basil (‘Baz’) Thompson was born in December 1915 in South Yorkshire, the third child (and second son) of Henry, a collier, and Edith. He worked briefly as a driver of pit ponies before joining the Royal Navy in March 1932 as a boy entrant, training initially at Ganges. Qualifying as an Ordinary Telegraphist in June 1933, he was in due course promoted first to Leading Telegraphist in 1938, and then to Petty Officer Telegraphist in 1940. ‘Baz’ married Iris Radford in Sheffield in May 1940. He joined Dunedin in April 1941.