Lambert signed with the Holdsworth cycling team for 1974 alongside Les West and Colin Lewis and won the British National Road Race Championships for the first time that year. He raced and finished Paris-Roubaix in 1977 before signing for Viking in 1978. At the 1979 World Championship at Valkenburg aan de Geul Lambert finished in 26th place of just 44 riders finishing including no other British finishers. In 1980 Lambert signed with Weinmann and finished third in the Druivenkoers Overijse behind Fons De Wolf and Rudy Pevenage and Lambert pipped Bill Nickson to the 1980 National Road Championship by an inch for his second British champion title in Redditch.