It is a prototype Healey 3000 Coupe, seen at Silverstone in 1968. It was built on a spare competition car from the 1964 Sebring race, and intended as a prototype ahead of a production run. Jensen was involved in the build, but politics and that bane of the British car industry, lack of funds, meant the project was canned, leaving just the X312 concept. There is some intersting info here along with photos of other prototypes by Healey. https://www.carsceneinternational.com/warwick-healey-motor-company-archive-bulletin-vii/