Jan was born on 21 April 1918 in Hamburg, Germany to Dr Wilhelm and Margaret née Bachrach who were living in Finchley, London at the time of his death. The family were born in Hamburg, Germany and Jan had a younger sister Stefanie. In 1939, the family were living at 18 Vivian Way, N2 where Wilhelm was listed as a Polish Advocate and Jan and his sister were students.

Jan was the navigator on Halifax LK794 which departed RAF Burn on an operation to Caen, France. The aircraft caught fire on the outbound route over Maidenhead and the pilot tried to divert away from the densely populated area below. The rear gunner F/S Hugh Sloan baled out before the aircraft rolled on to its back and dived vertically into the ground. Carrying a full bomb load, the aircraft exploded with such force that no trace of the six remaining crew was ever found. 

A/G, John Edward Claque, 1588531

W/Op, Lloyde Hinson Hopper, RCAF, J/86734

A/B, Ivor Morgan, 1337960

F/E, Gerald Thomas Nicholson, 1523535

Pilot, Victor Starkoff, DFM, RAAF, 414432

Rear Gunner Flight Sergeant Hugh Sloan, survived