Although Tim Parnell could never occur entirely in the footsteps of his famous father, he was able to achieve some success as a driver in motor sport. After a failed attempt to qualify for the 1959 Grand Prix of Great Britain, in 1960, he played a full season in Formula Junior.
1961 followed the entry into Formula 1 with the Lotus 18 he drove the races at Aintree and Monza. At the British Grand Prix he fell out, on the Italian tradition route he was tenth.
After 1962 he had to stay the whole year because of an illness, he returned in 1963 and became involved after the sudden death of his father to his team Reg Parnell Racing. The own racing career has been postponed. End in 1963, he ended his racing career and was team manager. After the end of Reginald Parnell Parnell team conducted many years of racing activities of BRM. In the 1960s, he managed the racing driver Mike Spence and Pedro Rodríguez.