[citation needed] In February 1973, Thomas became the first and only referee to send off the notorious Liverpool hard man Tommy Smith, although this was for speaking out of turn rather than foul play.
[4] During a long and sometimes controversial career as a referee in the old English First Division, he was known as "The Book" due to his strict interpretation of the laws of the game.
[7] Thomas was involved in another controversy when refereeing the semi-final of the FA Cup in 1977 between local rivals Liverpool and Everton.
With the game locked at 2–2 in the closing stages, Thomas disallowed what appeared to be a winning goal from Everton's Bryan Hamilton for handball.
Thomas refereed the 1981 Football League Cup final between Liverpool and West Ham United and was labelled a "cheat" by West Ham manager John Lyall after allowing a late goal from Alan Kennedy to stand, despite the prone Sammy Lee lying on the grass in an offside position.
In the extra time of that match, he missed a rough foul by Antonín Panenka on Johan Cruyff, after which Zdenek Nehoda was able to counter and score to give Czechoslovakia the lead.
[11][12] In a 2008 documentary by the Dutch TV program Andere Tijden Sport, Thomas admitted he made a mistake by not noticing the foul.