Garreth Carvell has made a swift U-turn on his contract decision

Great Britain prop Garreth Carvell has stunned Hull by asking for a move - just 24 hours after agreeing a new three-year contract.

The 28-year-old, whose old deal ran out at the end of the season, ended months of speculation by signing the contract.

But announcing his change of heart, Carvell said: "This could have been handled better on my part.

"I didn't want to let coaching staff and players down, which has made this the hardest decision of my career."

Hull, who say they will consider his request, will now be allowed to claim a transfer fee for a player who is still pushing for a place in the England squad for the World Cup in Australia.

Carvell, who missed last year's Test series with New Zealand through injury, has been linked with a move to St Helens but it is thought Bradford and Wigan could also be interested in his services.

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"For him to then come in and say 'I've changed my mind' is very surprising and naturally very disappointing.

"You work hard to retain your key players and for one of them to do such a dramatic U-turn is very frustrating.

"We now have to see what's available, what can we replace Gareth with and make sure whatever happens the club is not disadvantaged."

Coach Richard Agar, who gave Carvell a deadline to sign the deal, said he was "angry and upset" over the player's actions but would continue to select the player in his squad. The club have a Carnegie Challenge Cup semi-final with Wakefield at the end of the month.

It is a massive disappointment for us Hull coach Richard Agar

"It is a massive disappointment for us," said Agar. "However, when you are talking of contracts of this magnitude, I feel there has to be an element of players wanting to play for a club.

"Hopefully we can find a solution to this situation but in the meantime I have no doubt that Garreth will honour his existing contract to the best of his ability.

"We have an important semi-final coming up and I'll have no problem working with him.

"I know one of Garreth's goals this season is to make the World Cup squad and I am therefore confident he will play to the best of his ability to make that squad."

Carvell issued a statement reading: "First of all I would like to apologise to the supporters of Hull FC and reassure them I'll give 100% every time I pull on the shirt.

"There is still a lot to play for this season and I'm totally committed to getting something out of what has been a disappointing season so far."