Ever ambitious and eager to test new horizons, Keegan announced midway through the 1976-77 season that he would leave Liverpool at the end of the campaign.

It brought some criticism from supporters, but was another example of deception never being part of Keegan’s character, allowing Liverpool time to line up Kenny Dalglish as his replacement.

He went out on the highest high in his final game, running the great German defender Berti Vogts ragged as Liverpool won the European Cup for the first time, beating Borussia Monchengladbach 3-1 in Rome.

Keegan left having scored 100 goals in 323 appearances.

There was talk of a move to Real Madrid, but in the end his destination was Hamburg, where he was a major success as they won the Bundesliga in 1978-79, though disappointment followed when they lost the European Cup final to Nottingham Forest the following season.

Keegan confirmed his world-class credentials at Hamburg, winning the Ballon d’Or in 1978 and 1979.

Hamburg was a surprise choice when Keegan left Liverpool, but after early struggles to win over team-mates, he became hugely popular, not just with his club but in the country, where they appreciated the Englishman’s down to earth approach and his willingness to integrate.

It all added to Keegan’s status as a global superstar, one of the most marketable sportsmen around, not just seen on the pitch but in adverts and advertising hoardings worldwide.

He famously did an advert for Brut aftershave with British boxer Henry Cooper, as well as the “Green Cross Code” road safety campaign.

While in West Germany, Keegan had another crack at music with the track Head Over Heels In Love. It peaked at number 31 in the UK, but climbed to number 10 in the German charts.

Keegan returned to England in 1980 with a shock move to Southampton, showing his enduring quality by winning the Professional Footballers’ Association player of the year award in 1982.

He did not win trophies at The Dell, but was still a player of the highest class in Lawrie McMenemy’s team, built around experienced stars such as Keegan, Alan Ball and Saints’ great Mike Channon.