 Jameson took bronze in the 100-metre butterfly at the 1986 World Championships (Madrid), and then went on to take gold when representing England in the same event at the Edinburgh Commonwealth Games later that year.In addition to the gold he won a silver and bronze in the relay events and a bronze in the 100 metres freestyle.He went on to win the 1986 and 1988 ASA National Championship 100 metres butterfly titles, the 1988 ASA National Championship 100 metres freestyle title and the 200 metres backstroke title in 1982.