Keegan won 63 England caps over a period lasting almost a decade, scoring 21 goals and captaining the side 31 times.
It was a slow burner after making his debut in a World Cup qualifier in Wales, even including a physical assault by security men at Belgrade airport in summer 1974 when England arrived for a friendly against Yugoslavia under caretaker boss Joe Mercer.
There was horseplay at the luggage carousel, resulting in the perfectly innocent Keegan, one of the highest-profile players in the squad, being taken away to a side room, where he was punched and kicked. He was released, going on to score a late equaliser in a 2-2 draw.
Keegan briefly walked out of the England squad after being dropped for a home international against Wales in 1975, but returned after talks with manager Don Revie.
It summed up an England career that never fulfilled its potential.
England failed to qualify for the 1974 and 1978 World Cups, then when Keegan captained England at the 1980 European Championship in Italy, they did not progress from the group stage.
He was captain again at the World Cup in Spain two years later, but a chronic back injury – for which he left the camp to seek treatment from a specialist in Germany – meant he did not play until the last 26 minutes of England’s second-round game against Spain.
Keegan uncharacteristically missed a simple headed chance, the game ending goalless to send manager Ron Greenwood’s side home.
He was left out of Greenwood’s successor Bobby Robson’s next squad, and never played for England again.