Former England limited-overs coach Ashley Giles has claimed that the form of Alastair Cook should be a big concern for the team ahead of the World Cup.

There have been repeated calls for the captain to step aside as his difficult form continued in the series defeat to Sri Lanka, and Giles is still not sure whether the opener will be trusted to lead England into the tournament when it kicks off in February.

"Cook simply isn't playing that well," the Lancashire coach told BBC Sport. "He is under pressure.

"He hasn't been playing that well for a year and going into a World Cup your leader is important, but so is having 15 players in that squad who can perform and win games for England.

"I think there's still some discussion to be had and from the sort of the whispers we're hearing from the camp clearly they're not 100% sure. He is desperate to do well but he is still not getting the output that he would or England would want."

After the loss to Sri Lanka in the seventh one-day international, Cook once again insisted that he would not be stepping down as captain.