Designed as a 6×4 off-road vehicle for use in Britain's colonies where metalled (sealed) roads were scarce, the Pioneer was first produced in 1927.

Though lacking all-wheel drive, its combination of a suspension with great travel, excellent traction, and a low-revving engine gave it impressive pulling power on rough ground at low speeds.

Many Pioneer gun tractors were lost in France in June 1940 with the evacuation of the British Expeditionary Force (BEF), either destroyed by the withdrawing troops or captured by the Germans.

As this quantity was insufficient to meet requirements, the Pioneer was supplemented by the Albion CX22S heavy artillery tractor from late 1943.

Among the Pioneer's equipment was a pair of tracks that could be fitted over the two rear wheels, converting it temporarily into a half-track and giving greater traction on soft ground.

This was equipped with a longer wheelbase for an extended cab to accommodate the tank crew as passengers and larger rear wheels than the artillery tractor and recovery vehicle variants.