Lotus XI Frost leads Cooper T39 Gammon Silverstone 1956

Bill Frost's Lotus XI being chased by Peter Gammon's Cooper T39 Bobtail and what could be a Lister or a Lotus 10 perhaps?

The venue is Silverstone and the event is, I am fairly certain, the 1956 Daily Express International meeting.

(This is an amateur photo so please don't expect professional image quality).

10x7 inch (254x178mm)