Kevin Pietersen has, as expected, been dropped by England for the first time in his career and will play out the rest of the season while on loan with Surrey, after the selectors announced two squads of 12 and 14 players respectively for the two-Twenty20 and five-ODI NatWest Series against Pakistan that gets underway at Cardiff on Sunday.

Craig Kieswetter, the Man of the Match in the World Twenty20 final in Barbados back in May, has also been dropped from the 50-over squad following a loss of form during the mid-season internationals against Australia and Bangladesh. He has retained his place for the T20s, but his wicketkeeping role has been passed over to Surrey's Steven Davies, who takes the role in both formats ahead of the Test incumbent, Matt Prior.

Pietersen, who has fallen out with his county Hampshire after announcing his intention to leave at the end of the season, will play for Surrey until the end of the season, following a loan agreement between Hampshire and Surrey at the request of the England Team management and the ECB. He will play his first match for Surrey on Wednesday, a CB40 fixture against Worcestershire at The Oval, although he was not amused at the decision as he prematurely revealed in a rant on the social networking site, Twitter:

"Done for rest of summer!! Man of the World Cup T20 and dropped from the T20 side too. Its a f**k up!!," Pietersen posted on his account kevinpp24, before deleting it minutes later, but not before it had been picked up by several users and circulated around the internet.

Several hours later, his official, ECB-sanctioned, reaction was more measured: "While I'm naturally disappointed to have been omitted from the England squad I fully understand the reasons why and will be doing everything I can to get back into the England team," he said.

"I have no issue with the selectors omitting me from the limited-overs squads and my sole focus now is working on my game ahead of an exciting winter. I would also like to add my huge thanks to Surrey for giving me this opportunity and I hope I can repay them with some runs."

Geoff Miller, the national selector, said: "Kevin Pietersen has been omitted from both squads as we feel that his game would be best served by getting as much cricket under his belt as possible before a long and challenging winter.

"The remainder of the county season is an ideal opportunity to do just that and we thank Surrey for enabling Kevin the chance to play and we thank both Surrey and Hampshire for facilitating the loan period for the remainder of the county season.

"Kevin has proved on numerous occasions that he is a world class player and we know he'll benefit from getting more time in the middle to work on his batting and get his game back to the level he has shown throughout his career.

"Steven Davies has had an excellent year for Surrey this season and has earned his chance to take on the role as wicketkeeper in England's limited overs set up. As ever the wicketkeeper's role is a fiercely contested position in the England team and we've no doubt Craig Kieswetter will continue to press for the chance to reclaim his place in the England ODI squad."

England's 50-over captain, Andrew Strauss, will line up for Middlesex's CB40 fixture against Derbyshire on Saturday, September 4, before joining up with England's one-day squad on Wednesday ahead of the first ODI at Chester-le-Street two days' later.

While Ajmal Shahzad has been selected in the NatWest Series squad he will be available to play for Yorkshire throughout the campaign when deemed suitable by the England management.

Ryan Sidebottom will play the first half only of Nottinghamshire's County Championship match against Durham from Tuesday before joining the England Twenty20 squad on Thursday in Cardiff, while Kieswetter will play in Somerset 's 50-over tour match against Pakistan at Taunton on Thursday.

Meanwhile Ian Bell will also make his return from a foot injury with Warwickshire in their CB40 match against Nottinghamshire on Saturday, September 4.

Twenty20 squad Paul Collingwood (capt), James Anderson,Ravi Bopara, Tim Bresnan, Stuart Broad, Steven Davies, Craig Kieswetter, Eoin Morgan, Ryan Sidebottom, Graeme Swann, Luke Wright, Michael Yardy.

One-day squad Andrew Strauss (capt), James Anderson, Ravi Bopara, Tim Bresnan, Stuart Broad, Paul Collingwood, Steven Davies, Eoin Morgan, Ajmal Shahzad, Ryan Sidebottom, Graeme Swann, Jonathan Trott, Luke Wright, Michael Yardy.