His retirement, in the middle of an Ashes series already lost, is with immediate effect.
The 34-year-old bowler reasons that, where he was once a cornerstone of three successive Ashes series victories, he can no longer make an impact when his team need him to most.
He departs with Australia in an unassailable 3-0 lead and the urn gone, but Swann is convinced he has got his timing right. After three operations on his bowling elbow, the most recent last February in an attempt to nurse his career through 10 Ashes Tests in six months, he has fallen short of the standards he demands.
None the less, Swann finishes with an England off-spinner's record 255 Test wickets, above the great Jim Laker and behind only Derek Underwood among slow bowlers of any variety for his country. Swann's last seven were hard-earned, and costly at 80 runs each, but his inevitable mixed feelings at leaving on a low note after a failed campaign are far outweighed by a conviction that he had to be part of England's attempt to beat Australia again.
"It's easy to wish you'd gone out taking 10-for in your last game, and been hoisted on to people's shoulders as you walk off," he said. "But I don't regret a single day of the magnificent journey I've been on."
The worry now for England must be that Swann's retirement is the first of several as a team of world-beaters begins to show its age.
n South Africa gave up on the chance to set a new world record in chasing down 458 for victory against India on the last day of the first Test in Johannesburg yesterday, falling eight runs short as they settled for a draw in the closing overs.
The Proteas, needing 320 runs to win with eight wickets remaining, ended the match on 450 for seven, the third highest fourth innings score in test history, but played out successive maidens in the second and third last overs of the game to ensure they would not lose the match rather than go for the historic win.