Well that Lt. Cdr. B.H. Clinkard in his 4.3 litre Alvis single seater and I think it's Snetterton as that was his local circuit.
B.H. was Bryce Harben but everyone (including his son Tony and daughter Susie) called him "Clink". I last saw him at Snetterton supporting Tony who was racing a Ginetta. Sadly Tony was killed racing in 2002 - Clink himself died aged 85 in 2007
He built the Alvis to comply with the 4½ litre Formula 1 in about 1950, but eventually supercharged it and ran in Formule Libre racing which is what the photo shows as the following car isn't a GP single seater and you can't see the carbs as you could when it wasn't supercharged.