Shane Warne has launched a scathing attack on former teammate Ricky Ponting, saying criticisms he made of Michael Clarke in his recently released autobiography may be a result of "jealousy".

In an interview with the British press, the Australian Test great said he did not want to be "mean" about Ponting, before savaging his former skipper for airing dirty laundry on his "best friend" Clarke.

Ponting and Clarke exchanged text messages last week after tension simmered between the pair following the release of "At The Close of Play", in which Ponting was critical of Clarke's attitude under him when vice-captain.

However, Warne ensured the issue would boil to the surface again, suggesting Ponting could have been motivated to dig dirt because Clarke outperformed him in the latter years of his career.

"To bring up the stuff about Pup (Clarke) - maybe there was a bit of jealousy, because Pup was batting so well and Ricky was not making any runs," Warne said.

"To me, Michael's very well respected. The best captains keep stuff in the dressing room. No-one ever finds out about it. That's what good leaders are about. So to hear all this in a book is pretty ordinary.'"

During his frank assessment, Warne also decided to bring up Ponting's poor Ashes record, despite saying he regarded the Tasmanian as a good guy doing his best.

"I know he beats himself up mercilessly about being the only Australian captain ever to lose three Ashes," said Warne.

"And I know Ricky made that horrific decision to put England in at Edgbaston in 2005. I don't want to be mean about Ricky - he's a good guy and he tried to do the best he could."

Warne described Clarke as his best friend during the interview and said he considered him the best captain in world cricket.

Warne takes aim at England

Ponting was one of many targets for Warne, with the leg-spinner offering another damning critique of Alastair Cook's captaincy and claiming Joe Root will be "crucified" by Australia's bowlers if he opens the batting again in the upcoming Ashes series.

Warne said England would be better with Michael Carberry at the top of the order.

"I don't think Root's an opener because of his technique. Australia found him out in England and in Australian conditions they'll find him out more. You can't get stuck on the crease in Australia because of the pace of the wickets," he said.

"It could be crucifying him if he's got to face Ryan Harris, Peter Siddle and Mitchell Johnson on some fast, bouncy pitches. I think he's just going to nick off a lot. Besides Lord's, where he got 180, Australia really did have his number."

Warne has been accused of trash talking by England fast bowler Stuart Broad, but the Sky commentator disagreed and stood by his belief that Cook's captaincy could cost the visitors a fourth straight Ashes series victory.

"I think Alastair Cook needs to be more imaginative. If Australia play well and he continues to captain the way he does, I think they are going to lose the series," he said.

"I don't think he can captain like that and I'm not working in any capacity whatsoever for Cricket Australia.

"Darren Lehmann is a good mate of mine, and Michael Clarke is my best friend. Of course I speak to them a lot but I call it as I see it. And I'm not the only one who thinks Alastair Cook is a negative captain."

AAP