Petty Officer John Cooper was born in Stoke on Trent in Staffordshire on 9 March 1927, the son of Alfred Cooper and Lydia Cooper (née Shufflebotham).  There were two younger sisters - Joyce Mavis Cooper and Vera Lydia Cooper.

John Cooper joined the Royal Navy and then the Submarine Service and, by 1951 he was a Petty Officer serving in the ‘A’ Class Submarine HMS AFFRAY.  In January 1951 he married Sylvia Mansell in St Paul’s Church in Newcastle, Staffordshire.  On the afternoon of 16 April 1951, AFFRAY sailed from HMS DOLPHIN at Gosport with seventy five officers and ratings onboard comprised a reduced crew which included John Cooper, a training class of naval officers and engineers and a small party of Royal Marines.

HMS AFFRAY failed to make contact as expected on the following day and was assumed to have been lost with all hands in the English Channell overnight 16/17 April 1951. Following extensive searches lasting some two months the submarine was eventually located in the Hurd Deep in the Channel near Alderney.  It was established that HMS AFFRAY probably sank after being flooded via a broken snort mast.  The submarine was not recovered.

John Cooper is commemorated on the HMS AFFRAY memorial and plaque on The Esplanade in Gosport overlooking the Harbour Entrance which was unveiled on 16 April 2013 and on a similar memorial at Braye Harbour on Alderney which was unveiled in 2012.