Shane Warne has blasted Alastair Cook's captaincy as boring and negative, warning that Australia will regain the Ashes if the England skipper does not show more imagination.
The Australian Test great also said England would be better served by having Michael Carberry opening their innings rather than Joe Root.
In an interview with the British press and widely reported in Australia on Monday, Warne had harsh words about Cook's captaincy as England bid for their fourth straight Ashes series triumph in the series starting this month.
"Cook can be negative, boring, not very imaginative -- and still win and be pretty happy," Warne said.
"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.
"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, (Australia's) 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 (English) summer."
Warne also had a frank assessment of Root, claiming the young Yorkshireman will be "crucified" by Australia's bowlers if he opens the batting again in the series that starts in Brisbane on November 21.
"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," he said.
"You can't get stuck on the crease in Australia because of the pace of the wickets. 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 (Root) just going to nick off a lot. Besides Lord's, where he got 180, Australia really did have his number."
Former Test leg-spinner Warne said England would be better served by demoting Root to number six and bringing in Carberry to open with Cook.
Warne also took aim at former Australia Test captain Ricky Ponting, saying criticisms he made of Michael Clarke in his recently released autobiography could be a result of "jealousy".
"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.'"