The saloon was the Hillman Imp - the fastback body shown looks like the Sunbeam Stilletto.
I agree with sirjim it would be great to have the Hillman Imp to compete with the Mini especially if we also had the Ford Anglia (I will do a thread on that now if one hasn't already been started). For many years Minis, Imps and Anglias dominated the British saloon car racing scene in the up to 1 litre category and the up to 1300cc category and I have many happy memories of watching races between these three cars.
Clip from a recent race meeting shows Imps, Minis, Anglias, Lotus Cortinas in action: