Harold Lyon was born in Morningthorpe, Norfolk on 11 May 1890, the son of Alfred Owen Lyon and Adelaide Vernon Lyon (née Keane) of 3, Neville Terrace, South Kensington, London.  He joined the Royal Navy as a Cadet.

He was promoted to Midshipman on 15 September 1906 and was appointed to the battleship HMS SWIFTSURE on the same date.  He was then appointed to HMS DOMINION on 15 September 1908, followed by an appointment to the battleship HMS HINDUSTAN on 5 April 1909.  He was promoted to Sub Lieutenant on 30 November 1911.  After promotion to Lieutenant he was appointed to the battleship HMS EXMOUTH in August 1912.

He joined submarines with an appointment to the Submarine Depot Ship HMS ARROGANT at Portsmouth on 15 June 1913 ‘for Submarines’.  He was next appointed to the Submarine Depot Ship HMS MAIDSTONE  ‘for Submarine E2 as First Lieutenant’ on 23 June 1914.  HMS MAIDSTONE was transferred to the War Base of Harwich on the outbreak of War in 1914.  HMS E2 was later transferred to the Special Service Flotilla I based on the Submarine Depot Ship HMS ADAMANT at Mudros Harbour in the Mediterranean.

Lieutenant Lyon went missing on Wednesday 8 September 1915 after he was landed from E2 in the Sea of Marmora in an attempt to blow up a railway bridge near San Stephano – a similar feat to that performed previously by Lieutenant D’Oyly-Hughes of HMS E11.  Lieutenant Lyon was never seen again.  Harold Lyon is commemorated on the Portsmouth Naval War Memorial on Panel No. 7.

An extract from the patrol report submitted by HMS E2 reads:

“September 7

0330   Dived into Armudli till hit bottom at 50 feet.
Closed on shore.  Lieutenant Lyon swam inshore and destroyed 2 dhows.
1100   Sank dhow off Oxia.  Steered for Stefano.
1700   Dived into Kuchuk Chekmejah Bay, hit bottom.

September 8

Lieutenant Lyon proceeded inshore with a raft containing guncotton charge to blow up railway bridge.  Did not return.
0715   Dived out from land.
0815   Cruised searching for Lieutenant Lyon.  Nothing seen.”

From the Dundee Courier Monday 24 February 1919:
A NAVAL OFFICER’S DESIRE.
In his will Lieut. Harold Vernon Lyon. R.N., formerly of H.M.S. Maidstone, and of 13 Neville Terrace, Onslow Gardens, S.W., who was killed at sea on September 8, 1915, states:  “In the event of my departing this life during the present war, whether I am run over by motor car, or killed by a dog, it is my wish that no mourning is worn, and that nobody alters their existence on my behalf.  If I go, I go, and there is the end of it.” Should his body be available, he desired to be cremated “but I hope, if I have to go, my body will be buried at the bottom of the sea.”