Shane Warne has urged Andrew Strauss to be more adventurous in his approach as captain if he wants to lead England to success in this summer's Ashes series.

The 39-year-old gained as reputation as one of the finest cricket brains never to have captained Australia durirng his four seasons as Hamspshire skipper.

But as Warne prepares to join the Sky Sports commentary team for this summer's Ashes series, he is concerned that Strauss is developing into a conservative captain.

Strauss was accused of delaying his declaration in the third Test at Antigua, which allowed West Indies to survive with nine wickets down having batted through 128 overs to secure a draw and maintain their 1-0 series lead.

Warne believes England's demise to 51 all out in the first Test at Jamaica may have influenced Strauss' decision, but is now urging him to be bolder in his captaincy.

"I think we (Australia) would have given ourselves more time (to win the game), but having said that West Indies fought really hard," said Warne.

"I think enforcing the follow-on is over-rated anyway so in my opinion I don't think Andrew Strauss did anything wrong there.

"I just think they could have declared a lot quicker to give yourselves 150 or 160 overs. I thought that showed inexperienced leadership and it was probably also an after-effect of being bowled out for 51."

Warne stressed: "They need a captain to stand up and say, 'Listen boys, this is our style of play and if we lose, we lose, but we're going to try to win'.

"It would put the guys in situations where they might lose but the next time they are in that situation they will know how to win.

"The more times you get put in a situation where you could win or lose, the more you improve."

For all Warne's reservations about Strauss, though, he believes he should be given time to develop into the captaincy role this summer when England will attempt to overcome the humiliation of their 5-0 series whitewash in Australia two years ago under Andrew Flintoff's leadership.

"He's got a good head on his shoulders, he knows his own game and he's a good player," said Warne, "but whether he's got the imagination or the flair and the communications skills with all the players I don't know.

"It's very hard for a captain to come in, but you get better. No-one comes in as a brilliant captain straightaway, you get better and better.

"I think Andrew Strauss has a chance but you have to give him 12 months to see if he's any good and hopefully he'll grow into it. He's got the basics there, he just needs to back his judgement and stamp his own authority and not try to be someone else."

Although Strauss, who has only been appointed as captain for the current tour to the Caribbean, will be inexperienced in comparison to Australian captain Ricky Ponting, Warne believes there will be little to choose between the two sides when the series begins in Cardiff on July 9.

England have not won a series against a side ranked higher than them in the world rankings since Strauss, filling in as captain for the injured Flintoff and Michael Vaughan, guided them to a home success over Pakistan in 2006.

But Australia are also struggling to dominate as they once did, having lost Warne, Matthew Hayden, Adam Gilchrist, Glenn McGrath, Justin Langer and Damien Martyn to retirement since the last Ashes series.

The deciding factor in the series could be the fitness of all-rounder Flintoff, who is currently sidelined with a hip problem but confident of being fit to play in both the IPL and the Ashes.

"Andrew Flintoff is the key to England winning the Ashes," added Warne. "He is probably the best bowler in the world when he's on form and he's fit and firing and he drags the rest of the team along with his personality.

"He's inspirational, he's their go-to man and he's dreadful for left-handers as we saw last time with the way he bowled to players like Hayden and Gilchrist - if he's not playing Australia will win but if he is playing I think they're too pretty evenly-matched teams."