A Herefordshire-based gentleman farmer of Shobdon Court, Walker gained a certain notoriety for his aggressive, sliding style in Peter Whitehead's ERA before the war, and in the late forties became one of the few drivers to glean much success in the E-Type ERA both on the circuits and on the hills, where he put in some stunning performances in 1948.
He raced the ERA at the 1950 British GP with Rolt, but it soon failed. He did well to finish the race the following year, performing the most heroic single-seater deed by finishing seventh in the 1951 British Grand Prix with a 1.5-litre supercharged V16 BRM, after having half roasted in the stifling cockpit.
Signed by Jaguar in 1951 to race their sports cars, he shared his greatest triumphs with his old friend Peter Whitehead, the pair winning Le Mans in a C type and finishing second at Dundrod in the Tourist Trophy. In addition, Walker took second place at Le Mans in 1953, this time with Moss.
Moving to Aston Martin, Peter won the Goodwood 9 Hours with Dennis Poore in 1955 and raced a Maserati 250F at Zandvoort for Moss. He also drove at Aintree for Rob Walker.
He retired from racing after sustaining injuries when he crashed an Aston Martin at Le Mans in 1955, though he was tempted back one more time, to race Rob Walker's Connaught at Syracuse in 1957.
Sadly he ended his days an alcoholic derelict on the streets and in the shelters of the East End of London.