Commer was the name given to Commercial Cars Ltd when it was bought by Humber in 1926. Commer had manufactured Field Workshops to maintain Red Cross Ambulances.
Karrier produced 3,000 3/4 ton trucks for the services during WW1. It was later merged into the Rootes Group.
One of Bentley's major contributions to the war effort was the invention of the aluminium piston by WO Bentley which were subsequently manufactured by Humber.