Leonard was an Absolutist and refused to accept partial exemption from Military Service in the Non-Combatant Corps (1 Northern) in Richmond. He failed to report for Service on 24 May 1916 and was arrested. His case was heard at York Magistrates Court on the 28 July 1916 and he was handed over to the military authorities. Leonard was court-martialled in Richmond and imprisoned in Richmond Castle from 4 August for 112 days with hard labour.
Despite this harsh punishment, Leonard stuck to his principles, and was later imprisoned in Durham Prison (civilian). On 31 August, he appeared before the Central Military Tribunal at Wormwood Scrubs and was assigned to the Home Office Scheme (administered by the Brace Committee) on the 12 October 1916 on Dartmoor.
Leonard did not come from a Quaker background and his tribunal hearings were not reported in ‘The Friend’. He will have met a number of Quakers among the pacifists who were his fellow prisoners and on the Home Office Scheme. There is evidence that he did eventually become a Quaker – he married Ethel Brooks in a Society of Friends Ceremony at Ackworth in 1920.
Leonard died aged 74 in Wakefield in 1970.