On 21 January 1971 at the
MIRA high-speed circuit Dewis drove the only
Jaguar XJ13 for a film promoting the new V12 Jaguar E-type. Despite a damaged tyre, and against the instructions of Jaguar Director,
Lofty England, the car was driven by Dewis at high speed. The tyre failed and the car crashed heavily, almost destroying it. Dewis was unharmed. The wreck of the car was put back into storage. ==Work for Jaguar in retirement==