This is the Albion CX22 Heavy Artillery Tractor in the Land Warfare Exhibit at Duxford.
British WW2 6×4 heavy artillery tractor, crew of 1 and capacity for 6 gun crew with stowage for ammunition, powered by Albion EN244 6-cylinder diesel engine.
The Albion CX22S was designed and built by Albion Motors in late 1943 to supplement the Scammell Pioneer heavy artillery tractor, which was not available in sufficient numbers. In service the CX22S was used by the British Army to tow the 155mm Long Tom and the BL 7.2-inch howitzer.