Forbes joined Colchester United in September 1961 from Scottish non-league side Musselburgh Athletic, making his league debut later that season.
At Carrow Road, he helped the Canaries into Division One, and in 1970 he was voted the fourth winner of the Barry Butler Trophy, the fans' award for player of the year.
[2] Within a year of leaving Carrow Road, he returned, joining the Norwich City commercial staff where he was in charge of Club Canary organising trips to away matches.
Alongside Karl Duguid, Forbes was inducted into Colchester United's Hall of Fame at the club's annual Former Players' Dinner on 30 January 2016.
[5] Joint majority shareholders Delia Smith and Michael Wynn-Jones issued a statement remarking that "We have lost not only a club legend but someone who will forever be part of Norwich City folklore.
As a Spurs supporter, while meeting Duncan during a scouting evening in Europe a while ago... and having met many players over the years, found him to be a man that Norwich City must be very proud of.