Haslam debuted at the 1978 TT races with a best place of fourth in the Formula Two race, later making his mark in 1981, when he was named winner of the Formula 1 race, only for the organisers to give the win the following day to Graeme Crosby.
Haslam began competing at the 1978 TT races with a fourth place finish in the Formula Two category. In 1981, he was named the winner of the Formula 1 race but had his victory overturned by organizers and awarded to Graeme Crosby shortly thereafter.