Not a tank, but a tractor assembled from surplus Sherman tank parts. Vickers built these using bogies, tracks, GM diesel engine, gearbox and final drive from M4A2 Shermans.
Read more here:
http://www.mapleleafup.nl/g104/ploughshare.htm
Picture taken at the Vickers Elswick Works in April 1948
Source:
http://www.chroniclelive.co.uk/news/...s-show-9985844