Mysterious British Tank

The Soviet Union had an extensive network of intelligence agents in Great Britain, who were able to recover a great deal of information that the British weren't willing to hand over themselves. Sometimes that information was accurate, sometimes not so much.
"Characteristics
Of a 20-ton English tank

1. Mass: 20 tons
2. Armour thickness: 45-60 mm
3. Armed with a 6-pdr gun
4. Two diesel 130 hp engines, 4 drive sprockets on tracked chassis. These sprockets can also propel the tank if the track is knocked off.
5. Torsion bar suspension.