It represented the cartoon character invented and drawn by the war artist Bruce Bairnsfather for the Bystander magazines from 1915, which were eventually collected into the six-volume albums, Fragments from France.
The mascot helped to capture the mood of the British Army during and after the war.
This 4½in (11.5cm) high item is to be sold by Transport Collector Auctions in partnership with Lawrences of Crewkerne at its Automobilia and Historic Cycling sale on November 12.
Estimate £400-500.