Kevin Pietersen has questioned Alastair Cook’s credentials to be England captain and has voiced his dismay at a “bullying” culture he believes has long undermined the national team.

Pietersen’s autobiography, reveals his despair at the regime overseen by former coach Andy Flower in which he claims cliques took root and exerted an overwhelming negative influence.

The record-breaking South Africa-born batsman, axed by the England and Wales Cricket Board (ECB) eight months ago after the team’s whitewash Ashes defeat, is especially scathing about Flower and wicketkeeper Matt Prior.

He describes Cook as a “decent guy” but one “paralysed” by the situation he was put in.

Cook survived as captain following Flower’s move to a different job at the ECB and Pietersen’s sacking and remains in situ alongside returning coach Peter Moores as England embark on a World Cup winter.

But Pietersen, free to tell his side of the story following the end last week of a confidentiality clause agreed as part of his severance with the ECB, fears Cook may not be the right man to help forge the “new era.”

His doubts are bolstered by what he perceives as the opener’s failure to repay the sup

port he insists he gave his captain throughout last winter’s shambles.

“I was disappointed. I had gone out of my way to support him on the Ashes tour,” Pietersen writes.

“The next time I saw Cooky he was staring at his shoes while I was being told I would not be included in the England squads in the Caribbean or in the World T20.

“I was disappointed in him then. I thought the way he behaved called into question his qualifications to be captain.

“But I know too that he is a decent guy and that he was paralysed by how uncomfortable it all was.”

Pietersen spoke of his worries, in interview in the Daily Telegraph, that the ECB is in danger of “literally ruining Cook’s career.”

He added in his book: “Alastair Cook knows that on the Ashes tour there were absolutely no problems with me in the dressing room.

“Alastair Cook knows that I scored the most runs for England on that tour.

“Alastair Cook knows that I had his back 100 per cent.

“Any advice I could give, I did. I opened the door and said to him: ‘Listen, I am here to help you. I want you to be successful.’ I told him that again and again. If he needed me at any time, I would be there.

“I know, though, that while Cooky is a nice man, he is also a company man. A safe pair of hands, he won’t rock the boat.”