Liverpool have been warned that they will have to make an offer of more than £6million if they are to sign Birmingham City goalkeeper Jack Butland in the January transfer window.

The England international has repeatedly been linked with a move to Merseyside in recent months, with the Mirror suggesting that both Liverpool and Everton are keen to sign the goalkeeper in the New Year.

Jack Butland
Could Jack Butland end up moving to Merseyside in January? [Reuters]

Butland has only become first choice at Birmingham this season after earning plenty of plaudits for his performances for Team GB in the summer, which also helped earn him a call-up to the England squad under Roy Hodgson.

The 19-year-old was the subject of a £6million bid from Southampton in the summer, but Birmingham manager Lee Clark has made it clear that his value has increased after his excellent performances.

"By the time the window opens he'll have played 25 or so ­Championship games," said Clark, as quoted in the Mirror.

"We would be looking for an even more substantial figure than we were offered in the summer - even though I certainly don't want it to come to that."

Liverpool manager Brendan Rodgers has handed reserve goalkeeper Brad Jones a new contract, but it does seem as though he is keen to add a younger stopper to his ranks. It is also believed that he is unconvinced about Pepe Reina and may be looking to find someone suitable to challenge the Spaniard for the number one jersey.

Liverpool's Merseyside rivals Everton are also believed to be interested in Butland as their number two, Jan Mucha, is out of contract in the summer and could decide to leave on a free transfer.

With some serious interest from Premier League clubs, Clark has admitted that Birmingham may be forced to sell if an offer is simply too good to refuse.

"Ultimately, it's down to the board," Clark added. "He's the future and the type of player I'd rather build my team around."