John ‘Jack’ Travers Cornwell was born on the 8th of January 1900 in Clyde Cottage, Clyde Place, Leyton. He was the son of working-class parents, Eli and Lily Cornwell (formerly King) and had two brothers: Ernest, born in1898, George (1901) and a sister Lily (1905). He also had a half-brother named Arthur (1888) and a half-sister named Alice (1890). Their mother was Alice Cornwell (formerly Carpenter).

The family moved to No.10 Alverstone Road, Little Ilford, Manor Park, in 1910. Jack attended Walton Road School in Manor Park and was a keen Boy Scout in the Little Ilford Troop at St Mary’s mission. When Jack left school he became a delivery boy for Brooke Bond & Co. and then worked as a dray boy with the Whitbread’s Brewery Depot in Manor Park.

At the outbreak of war, Jack’s father Eli, an ex-soldier, re-enlisted as a Private in the 57th Coy. Royal Defence Corps. It was The Royal Navy that appealed to Jack and at the age of 15 he took references from his Headmaster and his employer along to a local recruitment office and enlisted.