The inevitable confirmation, when it came, dropped on to the Tottenham Hotspur website at 11am on Thursday morning. Ledley King, described as one of the club's "greatest players", has been forced to retire after years labouring with a chronic knee complaint. A one-club man who had first joined up at 14 and had spent the last 13 years in the Spurs first-team is bowing out after 323 senior appearances and 21 international caps.

Neither those figures nor the plunder accumulated en route – amounting to a Carling Cup in 2008 – actually do the defender justice. A classy, imperious defender with a wonderful eye for reading the game has departed the scene.

His was the right decision. King finished last season in a lot of pain and, ever since, had been forced to confront the potential damage he might do to his body by playing on. At 31, he was concerned that he might not be able to do himself justice this season when André Villas-Boas kickstarts a new era at White Hart Lane. He did not want to be remembered as a passenger in this Tottenham squad but, quite rightly, as one of the finest central defenders of his generation.

That much is understandable. He was a player capable of summoning majestic tackles from desperate situations, a captain whose natural attributes – in the air, on the turf, in possession – might be deemed more rounded than, for example, Rio Ferdinand or John Terry, a pair who have accumulated 158 caps between them.

He will be remembered fondly from those on the outside, and as an icon by the Spurs support, with the only frustration the reality that thoughts forever drift to what might have been had King actually been fit. The medics had anticipated this day would come four years ago. The centre-half has no cartilage in his left knee and is unable to train with his team-mates between games, and yet has still been unflustered and up to pace for much of his career when available. His doctor has described him as "superhuman", a player who has "defied science".

The former Tottenham manager Harry Redknapp would regularly marvel at his ability to pluck form on a Saturday, slipping seamlessly back into the rhythm of a ferocious Premier League contest, after a week of rehabilitation and training in the swimming pool or gym. Fabio Capello saw so much in his performances that he took him to the World Cup in South Africa, despite the fact that the defender was never likely to be able to play any more than a bit-part role in the finals. Such was his obvious quality.

Fitness was fleeting, but class was permanent. Even in recent seasons, Spurs were a different team when King started matches, those around him gaining assurance from his mere presence on the turf. It was only in the second part of last season that his performances really tailed off and the strain clearly showed, a collision with a youth-team goalkeeper on one of the rare occasions he could train, over Christmas, having set him back.

Perhaps he should have undergone his annual clean-up operation on the joint early, but instead chose to wait until the summer to visit the surgeon. As it is, the knee can take no more and the time has come to move on.

An ambassadorial role awaits at White Hart Lane for the youth-team product whose loyalty was cherished. One-club men feel a rarity these days, and Spurs were so scorched by Sol Campbell's defection to Arsenal that King was instantly lauded as a legend from the stands.

"I have been here since I was a boy, I have always considered it my club and have always found it hard to imagine wearing the shirt of another team," he said. "I have always enjoyed being part of the set-up here and the challenge of putting this club up with the elite where it should be." He leaves as Villas-Boas attempts to further that transition but, when he is paraded on the pitch – as also feels inevitable – in the new season, those at the Lane will chorus their thanks.