Commer Q2 Tractor with a Hawker Tempest on a Queen Mary trailer during the Victory parade in London, 8th june 1946.
This is a Militarised Superpoise, officially known as 'Tractor, 4x2, Light, 10'0" WB, Type Q2', also referred to (by RAF) as '4-ton tractor'. Produced in 1945, chiefly for towing 'Queen Mary' aircraft-transporter semi-trailers.
There is only one known survivor of this type of Tractor. It was last seen for sale in the Netherlands ca. 2016 and has since disappeared off the radar.