Former Australia coach John Buchanan has identified Kevin Pietersen as the potential weak link in the England side looking to retain the Ashes this winter.
Pietersen has struggled for form of late and is currently playing for Dolphins in South Africa in a bid to rediscover his touch ahead of the trip to Australia.
Australia skipper Ricky Ponting has already taken a swipe at the former England skipper, describing him as a vulnerable part of the tourists' side.
And now Buchanan, who worked on a consultancy basis with England last summer, claims Pietersen could be a major problem over the winter.
"They [England] seem to have a new mental toughness and they are more consistent, except for the odd glitch, which is mainly Kevin Pietersen," Buchanan tells The Wisden Cricketer.
"He is a quality player and he could be an incredible strength for them but, if he's not scoring runs, he could become a major problem for the batting line-up and the entire team. Andy Flower has been trying to work on that.
"Pietersen hasn't done himself or the team any favours with his recent twittering. Two of the things that will be tested in Australia are strength and unity and clearly he hasn't understood his role within the team yet. He has the potential to be an individualist and fragmentary. It needs to be managed by [Andrew] Strauss and Flower."
Buchanan has a history of criticising Pietersen, describing him as a "man apart" and selfish for refusing to bat higher up the order during the Ashes series of 2006-07 and clearly feels his barren run of form in Test cricket is a potential pressure point for Ponting and his men to exploit when the Ashes series begins in Brisbane in November.
Buchanan had envisaged a more long-term role with the ECB when he arrived in England last summer but later claimed they couldn't afford his fees. Criticism of England's leading talent may not be the best way to gain future employment but he is clearly impressed with the management of Strauss and Flower, claiming they can make the team the best in the world.
"The future looks very healthy and I believe England can be world leaders within the next three years," he said. "The pathways and people they have in place could see them overtake the rest of the world."
Buchanan goaded England by asking them to give Australia "a contest" during the whitewash of four years ago but senses a different result this time, providing they remain united.
"None of them has any experience of winning in Australia," he said. "Playing overseas is very different and they have yet to prove they can do it over a five-Test series in Australia.
"At some point doubts will start to creep into their heads and it is all about how they deal with them. They need to retain this spirit and sense of purpose.
"England teams in the past would often be beaten before the Test started. They didn't believe in themselves, even when they were ahead, but they are better at handling that now. The top four, Strauss, Cook, Trott and Pietersen, will be England's most important players. That is where the series will be decided. Whoever wins the battle of the top fours will win the series."
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