Henry Toppin was the son of Charles Toppin (a schoolmaster) and Daisy Toppin. He was born in Upton on Severn, Worcestershire, on 17 April 1903. He had one brother, Charles, and three sisters, Maud, Nora and Ruth.

He joined the Royal Navy as a Cadet on 15 January 1917. Promoted to Midshipman on 15 May 1921, he joined the battleship HMS RAMILLIES. He next served in the destroyer HMS VAMPIRE from 15 August 1922 before rejoining HMS RAMILLIES on 14 December 1922. Henry Toppin was appointed to HMS VICTORY for his Lieutenants Courses at Portsmouth on 12 November 1923. On completion he was appointed to the destroyer HMS WALPOLE on 9 June 1925 then to HMS DOLPHIN ‘for the Submarine Course’ on 6 July 1925 and ‘for Submarines’ on 18 December 1925.

An appointment to the Submarine Depot Ship HMS CONQUEST ‘for Submarine K26’ followed on 1 January 1926. Promoted to Lieutenant on 15 October 1926, from 11 February 1927 he was appointed to several depot ships ‘as Spare First Lieutenant’. This was followed by an appointment to ‘Submarine L71 as First Lieutenant’ on 15 December 1927’.

Henry Toppin next qualified as a Pilot from No. 10 Naval Pilot’s Course which was conducted at the RAF Leuchars in Fife from 14 March 1928. On qualifying he was appointed to the aircraft carrier HMS COURAGEOUS ‘for No. 404 Flight RAF’ in December 1928. On 10 April 1929 he was flying a Fairey Flycatcher. When landing on, the aircraft hit the superstructure and the aircraft was written off and Henry Toppin slightly injured. He was flying again two days later on 12 April 1929 when an accident with a Fairey IIIF occurred. He had been carrying out a bombing practice run from HMS COURAGEOUS and, when landing on after this run, he fouled the trip wire of the port side palisades with his starboard wheel. The aircraft swung at right angles and crashed into the island. Toppin was cut about the face and the aircraft was written off.

Henry Toppin was appointed to HMS DOLPHIN ‘for Submarine M2’ on 21 September 1931 and ‘for Flying Duties at Lee on the Solent’ on 1 October 1931. HMS M2 was lost with all hands in an accident in West Bay near Portland. It is believed that the submarine had surfaced to fly off its Parnell Peto seaplane when it was accidentally flooded through the open aircraft hangar door and submarine access hatch.