Sgt. Williamson was serving with 189 Squadron. He was a crew member of Lancaster I PB742 CA-F which flew from Fulbeck on a mission to Hellbronn. All crew members died.
Royal Air Force Bomber Command Losses of the Second World War 1944;4 W.R. Chorley; Midland Counties Publications 1997; ISBN 0 904597 91 1
James Ashcroft Williamson is remembered in Murton on M47.01, M47.07, and M47.08 and in Monkwearmouth on M46.02 page 123.