Watt beat such notables as future world champion Sean O' Grady, former world champion Perico Fernandez, Charlie Nash and Howard Davis Jr. The fight with O' Grady was particularly controversial: Watt won by a knockout in round twelve when the referee stopped the fight because of a cut suffered by O' Grady. According to the book, The Ring:Boxing in the 20th Century, the cut was produced by a head-butt, in which case the judges' scorecards would have been checked, and whoever was ahead given the win by a technical decision. The referee, however, declared that O' Grady's cut had been produced by a punch, therefore, Watt officially won the fight by knockout.
Watt also fought, and lost to, Ken Buchanan. On June 20, 1981, he fought his last fight, when losing the WBC world Lightweight title to Alexis Arguello by a 15 round decision in London. Watt had closed the curtain with a record of 38 wins and 8 losses, 27 of those wins coming by knockout.
Although he was able to stay away from boxing permanently, he has been active as a public figure in retirement: He is, alongside former world Middleweight champion Alan Minter, a guest dinner speaker and autograph signer, and he was given an MBE by HRH Queen Elizabeth II.