Swallowed up by the Gallowgate after his debut goal, sealing promotion two years later on a sunny afternoon against Brighton, leaping up from the bench with Terry Mac against Bristol City. Standing on the steps to explain Cole’s sale. Loving it, just loving it on Sky. And the helicopter, of course, always the helicopter. We’ve lived and re-lived those images of Kevin Keegan’s life until they’re as familiar as our own family photos and memories.

The fascination of Brian Moore’s 1979 documentary about Keegan, currently available on the ITV Hub, is its capacity to surprise. This is Keegan the player at the absolute peak of his powers, not in those years at Liverpool and Newcastle which we know so well, but in the unfamiliar surroundings of Hamburg.

I’d read about his success on the pitch in Germany, but I’d never seen him wheel away after scoring to accept the acclaim of the Volksparkstadion on the final day of the season when Hamburg became champions for the first time. I’d read about his popularity, but I’d never seen him on the balcony of the Hamburg town hall in front of thousands of German fans chanting his name or interviews with German teenagers outside the ground professing their love.

I knew Keegan was a fine athlete in his prime, but I wasn’t prepared for the ripped muscularity of his physique that catches the eye in every shot. I’d heard that Keegan had picked up the language while in Germany, but I didn’t expect the fluency and idiomatic ease with which he chatted to shoppers in his local supermarket.

Above all, this is a film about Keegan the man. And it’s the insight into the man behind the public face of the world’s most famous footballer that make it so compelling, whether it’s talking about his mother and father and the work ethic they passed on to him or wandering around the shops with Jean and with little Laura strapped to his chest.

Surprising also is the frequency and detail with which Keegan talks about money. He talks about it a lot. In fact, he talks about it almost all the time. How much more he earns at Hamburg than at Liverpool, how much his house cost, how much he earns for an hour signing autographs. This is a portrait of Keegan the commercial and entrepreneurial pioneer. Clearly, his own origins and his father’s workplace illness spurred him to make the most of every opportunity. Mind you, it’s still a relief to hear him turn down a request from his business manager for a personal appearance from Thatcher.

But the two most central themes of the film come as no surprise: Keegan’s determined single-mindedness and his natural human warmth.

The former is apparent as he talks about his early struggles in Germany with teammates who resented his outsider status, who wouldn’t talk to him, and who wouldn’t pass to him. After six months in Germany with a struggling team and a sacked manager, facing an eight-week suspension for punching a player in a mid-season friendly, and pilloried in the English press for going abroad, it would have been easy for Keegan to give up. Instead, he did what he always did and willed himself to succeed, in the process becoming the only British footballer to win the Ballon d’Or twice.

But my favourite moment comes on a visit to France where his new brand of football boots are being made. Exaggeratedly taking the hand of one of the middle-aged French factory workers, Keegan kisses it like a chivalrous prince and she melts before our eyes. Much like a whole city would three years later. And every moment thereafter.

Matthew Philpotts @mjp19731

“Brian Moore meets… Kevin Keegan” is available on the ITV Hub 

You can read more about Keegan’s Hamburg years in the forthcoming issue of True Faith, available soon.