Four, six, dot ball, six, dot ball, six – Graeme Swann’s last over in international cricket strongly backs his argument that it’s time to quit.

The English off-spinner raised eyebrows on Sunday ahead of the Boxing Day Test by retiring from Test and first-class cricket immediately, rather than waiting until the end of this Ashes series.

But by the time Shane Watson belted him out of the attack with that 22-run over in the second innings of the Perth Test a week ago, Swann had made his decision.

He came to the conclusion during the second Test in Adelaide and mulled it over before Saturday, when he told England coach Andy Flower and captain Alastair Cook.

“I know I’m making a decision for the right reasons,” he said at Sunday’s media conference.

“My body doesn’t like playing five-day cricket any more and I don’t feel like I can justify my spot in the team in the last stages of a game.

“As a spinner, that’s when you need to come into your own.

“Me hanging around with a decision already made in my head wouldn’t be right.

“It would be selfish for me to carry on.”

There was immediate and widespread praise for Swann, who took 255 wickets in 60 Tests and played a key role in England’s previous three Ashes series wins.

But Australian paceman Ryan Harris summed up surprise about the timing of the announcement.

“Something’s obviously not quite right with him, or he’s fulfilled whatever he wanted to do, but to me that’s a huge shock,” Harris said.

Australian coach Darren Lehmann was more philosophical.

With England 3-0 down and having lost the Ashes, Lehmann was asked what his reaction would have been if one of his players had wanted to retire when Australia faced the same plight only a few months ago.

“Senior players, if they feel like they can’t contribute how they’d like, that it would be their decision,” Lehmann said.

“It’s always tough mid-tour.

“All I can say … is he’s been a great bowler for England and he’s obviously decided enough is enough.”

It is another massive blow to England, whose Ashes tour of great promise has unravelled.

The Australians have mauled Swann, who had taken only seven wickets in this series at an average of 80.

Top-order batsman Jonathan Trott also left the tour after the first Test because of personal issues.

Apart from Swann’s undoubted cricketing ability, England will also miss his team spirit.

“The dressing room will be a very different place without Graeme’s unique personality,” Flower said.

Swann wants to be remembered primarily as someone who loved playing the game.

“Since I got back (into the England team in 2008) I’ve treated every day like a lottery win,” he said.

“It really annoys me when people out there take it for granted and get above their station … it’s the most privileged thing any man can do.”

Swann said in hindsight he could have retired after the previous Ashes series in England earlier this year.

“But I’d never forgive myself – we had the chance to potentially come out here and win four Ashes series on the bounce,” he said.

Swann said his social media gaffe, where he apologised for comments after the Perth Test loss, had not helped prompt him to retire.

The Englishman received praise from his opposite number in the Australian team, Nathan Lyon.

“He’s someone who I’ve looked up to a lot,” said Lyon on the Cricket Australia website.