Robertson had played for Scotland at schoolboy and youth level before joining Forest as a teenager in 1970. He had failed to make an impact until Clough’s appointment, but the great manager saw something he could nurture.

In his autobiography Clough wrote: “Rarely could there have been a more unlikely looking professional athlete… scruffy, unfit, uninterested waste of time… but something told me he was worth persevering with and he became one of the finest deliverers of a football I have ever seen.”

He also wrote: “If one day, I felt a bit off colour, I would sit next to him. I was bloody Errol Flynn in comparison. But give him a ball and a yard of grass, and he was an artist, the Picasso of our game.”

Clough was idolised by Robertson, who said: “I knew he liked me but I loved him. I wouldn’t have had a career without him.”

Robertson played in 243 consecutive games between December 1976 and December 1980, and despite the big-name buys such as England goalkeeper Peter Shilton and Francis, Britain’s first £1m footballer, he was the player who made Forest tick.

For all the talent elsewhere, Robertson was Forest’s fulcrum.

In Forest’s first season back in the top flight under Clough in 1977-78, Robertson not only played a vital role in winning the title, but also scored the winner from the penalty spot against Liverpool in their League Cup final replay at Old Trafford.

It was not just Clough who recognised Robertson’s significance, with former team-mate Martin O’Neill saying: “He was the most influential player in Europe for maybe three-and-a-half to four years.”

And Forest’s captain under Clough, John McGovern, stated: “He was like Ryan Giggs but with two good feet.”

All this despite Robertson’s own admission that he had no pace and could not tackle.

Clough, however, was not bothered about what Robertson could not do, preferring to give him licence to concentrate on what he could do. It was the perfect footballing marriage of manager and player. Two maverick characters working in harmony.

In a famous interview before the 1980 European Cup final against Hamburg, who had England captain Kevin Keegan in their side, Clough was asked about the prospect of their great Germany right-back Manfred Kaltz keeping Robertson quiet.

“We’ve got a little fat guy who will turn him inside out,” said Clough. “A very talented, highly skilled, unbelievable outside-left.”