He was a player of great contradictions. Far from being a dedicated, ultra-professional athlete, legend has it that he existed on a diet of pies and cigarettes.
Clearly, this is embellished to a greater or lesser extent, but it is no secret that when Brian Clough and Peter Taylor assumed control of Nottingham Forest Robertson was overweight, languishing in the reserves and questioning his future in the game.
Clough asked him to change his position from central midfielder to left-winger, and he never looked back.
Despite his team-mates considering him to be the slowest player at the club he was a massive success out wide, winning the Second Division Player Of The Year and then becoming a key part of the side which adapted so well to life back in the First Division.
By May 1980, his transformation was complete. Having set up Trevor Francis' winner in the previous European Cup final, he went one better.
Exchanging a quick one-two with Garry Birtles as he cut in from the touchline, he drilled the ball past Rudolf Kargus in the Hamburg goal and in so doing sealed Forest's second consecutive European triumph.
Disclaimer: The views in this article are that of the writer and may not replicate those of the Professional Footballers' Association.