マーチ・エンジニアリング
Williamson was born in Ashby-de-la-Zouch, Leicestershire. He won the 1971 and 1972 British Formula 3 Championship titles. In 1973, he was offered a drive in the March Engineering works Formula One team. Williamson originally tested for the BRM team, but his manager advised him to take the March offer, as March had a slightly stronger performance in the previous season.