John Lennon was born on 15 August 1879 in County Tyrone, Ireland and joined the Royal Navy on 6 March 1915.  His occupation prior to enlistment was a fitter. He was the husband of Mary Lennon of 3 Middle Lane, Paisley, Renfrewshire. He drowned in the Mediterranean off Pyrgos when a dinghy he was in capsized. The report into the drowning stated that he was missing believed drowned along with AB Alfred Whitehorne (q.v), also of HMS E25. No further trace of of men or boat was found, its loss the result of a sudden gale without warning just before dark. No Court of Inquiry to be held as no further evidence could be obtained.
He is commemorated on the Portsmouth Naval Memorial and on a memorial in the Capuccini-Kalkara Naval Cemetery in Malta.