Alastair Cook must stand down as ODI captain, says Sir Ian Botham

England legend Sir Ian Botham says the time has come for under-fire captain Alastair Cook to stand down from the one-day side.

Cook has come under increasing pressure over his role in England's 50-over team, with the 5-2 series defeat by Sri Lanka representing their fifth in a row under his leadership.

The 29-year-old has also been well short of his best as a batsman, averaging 19.83 in Sri Lanka, and Botham said Eoin Morgan should take the captaincy - which he assumed when Cook was suspended for the fourth-ODI - on a full-time basis.

"I personally wouldn't play Alastair Cook. I'm saying that now but I've been saying it for a year," Botham told Sky Sports News HQ.

"I think Alex Hales is a far better bet for the kind of cricket we want to play in Australia. When Eoin Morgan was captain he made a 50 and that's who I'd give the reins to for the World Cup."

Cook has admitted his performances have been short of his standards, but reiterated his "hunger" to continue in the role.

Botham insisted Cook - who has received consistent backing from the ECB amid the ongoing criticism - should stay on as Test captain.

"This is not personal. It's purely and simply on what I've seen in one-day cricket," he said.

"I think he should stay as England's Test captain, I think he can be there for as long as he wants and score lots and lots of runs.

Even in his best form he's not a devastating one-day player and he's nowhere near his best form

"It's not for me to talk about his skills. He's proved himself in the Test arena and has the skills but I think trying to play one-day cricket is affecting that so I would say he should have a good rest and a break: there's a lot of Test cricket coming up after the World Cup."

Meanwhile, former England batsman Mark Butcher said the debate over Cook's captaincy was virtually redundant, given his ongoing struggles as a batsman.

"My view is to ask whether he gets into our best XI and the answer to that is 'no'," said Butcher.

"He isn't good enough to get into one of those top-six batsmen roles so England are having to unbalance their side in order to accommodate him.

"It leaves you with little chance of making a major impact at a big tournament. Even in his best form he's not a devastating one-day player and he's nowhere near his best form."

But Butcher said he doubted whether the ECB would jettison Cook so close to the start of a World Cup, with the tournament getting under way on February 14.

England will name a 15-man squad for the World Cup on January 7, but first of all a 16-strong squad has to be selected for the triangular series against Australia and India.