Leonard John was born in Chertsey, Surrey to Frederick James Oldacres and his wife, Fannie Kench. He was the youngest of their five children. His only brother had died shortly after birth.

His mother came from Warwick where the Kench family had been fine flour millers for several generations. Her brother, Leonard, had been killed in action in 1916.

In the summer of 1929, Leonard with his parents and sisters, Janet and Ruth, visited Canada where his oldest sister Priscilla who described herself as a church worker, was living. In 1940, she married a clergyman in British Columbia and died in 1948.

For many years, the Oldacres lived at Pyrford House, Woking, Surrey where his father, an architect, died on 17 June 1932 leaving £19,189-19-11.

Leonard was educated at Winchester and Matriculated in 1935. He graduated with a 3rd in PPE in 1938. After going down, he was Articled to a firm of Chartered Accountants.

He was gazetted to the RAFVR on 15 December 1936 and was called up at the outbreak of the war.

He was a Flying Officer based at Lille-Ronchin with No 4 Squadron when his plane and a plane flown by John Plumb, were attacked and shot down at about 10 o’clock on 5 May 1940. Hurricanes from No. 87 Squadrons based at Bondues, took off and pursued the two Bf-109s which had attacked. One was shot down and crashed near St Amand.

He is buried along with John Plumb and their air gunners, Clarence Butterill and Ronald James Thornton at St Andre Communal Cemetery Row AA. Grave 7.

He is commemorated on the Pyrford Church War Memorial