London, July 27: England left-arm spinner Ashley Giles is to undergo an operation on his injured achilles tendon that could see him out of action for up to six months the England and Wales Cricket Board (ECB) said in a statement here on Friday.

The Warwickshire bowler will have the operation on Monday, so missing the rest of the English season and the three remaining Ashes Tests against Australia.

The statement said that Giles, 28, who during the winter established himself as England's leading slow bowler, would also miss the one-day series in Zimbabwe that starts in September.

But it added the "board is hopeful that he will be in contention for a place on the winter tours of India and New Zealand" that follow.

Problems with his achilles have troubled Giles for several seasons and questions are bound to be asked as to why, when he had bowled through an increasing pain barrier in Pakistan and Sri Lanka, he did not have surgery immediately upon his return.

Instead the authorities opted for a rehabilitation programme that, in the end, has not worked as the statement admitted.

"Giles, who underwent a six-week rehabilitation programme earlier this summer in an effort to cure the chronic injury, is expected to be out of cricket for between four to six months," the statement said.

"The injury did appear to be much better after he underwent an extensive programme of strengthening and rehabilitation work following his return from Sri Lanka.

"Unfortunately, after he started playing cricket again, he was unable to continue with his rehabilitation work to the same degree and the injury deteriorated again.

"As a consequence, the ECB medical team has reviewed Ashley's case and decided that surgery now represents the best way forward for him. The board's medical team has discussed the situation with Warwickshire and they are fully supportive of this decision."

In Pakistan, Giles topped the England bowling averages with 17 wickets at 24 as England won the three-match series 1-0. But his wickets in Sri Lanka were more expensive, seven dismissals, costing 44 a piece.

In his one Test appearance this season, during the First Test innings defeat by Australia at Edgbaston, he took one for 108.

Giles is one of a number of England cricketers who have suffered with injury problems this summer. England captain Nasser Hussain (finger), batsmen Graham Thorpe (calf/hand) and Michael Vaughan (knee) plus all-rounder Craig White (back) have all missed Tests.

So far this season England have drawn the two-match Pakistan series at one apiece before going 2-0 down to Australia ahead of Thursday's third Test at Trent Bridge.

Giles' absence could lead to an England recall for Test predecessor Phil Tufnell.

The 35-year-old Middlesex left-arm spinner, played the last of his 41 Tests 18 months ago but is currently the leading English spin bowler in this season's first class averages with 44 wickets at 23.02.

England opted for an all seam attack during the second Ashes Test at Lord's and still lost by eight wickets.

They must win all three remaining Tests to win their first Ashes campaign since 1986-87 and to do that they must bowl Australia out twice in every match.

Those considerations could see Tufnell, who has taken 120 Test wickets at 36.55, recalled in a bid to add much needed variety to the attack.

England are expected to name their squad for Trent Bridge on Sunday.