- The Ashes
Warne slams 'negative, boring, unimaginative' Cook
Cook's leadership of England has thus far been characterised by a close relationship with the coach Andy Flower and a calm guiding hand rather than any great invention in the field. England's preferred approach is of a more conservative nature than that of Michael Clarke and the Australian coach Darren Lehmann.
And in a typically showstopping stream of opinions ahead of Australia's return bout with England, Warne said: "If Michael Clarke did the same things, I'd say he was negative, but he's not. That's not the way he captains.
Cook can be negative, boring, not very imaginative - and still win and be pretty happy. But I think he needs to be more imaginative. If Australia play well and he continues to captain the way he does, I think England are going to lose the series.
"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.
"He lets the game drift. He waits for the game to come to him. I don't think he can captain the side like that. For me, Michael Clarke is the best captain in the world at the moment. He just has a lot of imagination. Cook would never have a leg slip, bat-pad and leg gully, like Clarke did for Jonathan Trott in the summer."
Warne, speaking to Sky Sports, for whom he is a commentator for The Ashes series, added that England would do well not to play Joe Root at the top of the order during the series, suggesting the young Yorkshireman would be "crucified" facing the new ball on Australian pitches. Warne preferred to see Michael Carberry as Cook's opening partner, with Joe Root to bat at No. 6 instead of Jonny Bairstow.
"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.
"It could be crucifying him if he has 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 also accused Ricky Ponting of being motivated by "jealousy" in criticising his Australian captaincy successor Clarke, while also asserting that will risk losing the Ashes for England should he continue to lead in a "negative" manner.
In a typically showstopping stream of opinions ahead of Australia's return bout with England, Warne leapt to the defence of his "best friend" Clarke, arguing that Ponting's written critique of the incumbent leader in his autobiography was the result of bitterness. He also said Ponting's actions did not compare favourably with those of Allan Border and Mark Taylor, the "two best captains" the former legspinner played under.
"I know he beats himself up mercilessly about being the only Australian captain ever to lose three Ashes," Warne said in a press conference call with English media for the Ashes broadcaster Sky Sports. "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.
"But 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. 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."
Daniel Brettig is an assistant editor at ESPNcricinfo. He tweets here