David Locke was born on 16 February 1921, the son of George Sydney, a Civil Servant, and Jeannie Brebber Emslie Locke of Wandsworth, London. In the 1939 Register he was listed as being at school in Wellington College in Crowthorne, Berkshire. He was further educated at Clare College, Cambridge.

He joined the Royal Navy Volunteer Reserve as a Temporary Sub Lieutenant with a seniority of 30 April 1942. A volunteer for Special Service he was appointed to HMS VARBEL and trained as a diver for X-Craft submarines. He was the First Lieutenant of HMS X7. During a training exercise in Loch Striven on 31 May 1943 he was lost accidentally during a net cutting procedure – his body was not recovered.

David Locke of 12, Fisher Drive, Southport, Lancashire is commemorated on the Portsmouth Naval Memorial on Panel No. 80 Column No. 1 and on the 12th Submarine Flotilla Memorials at Rothesay on the Isle of Bute and at Kylesku.