Everton boss Roberto Martinez has promised that not even a world record transfer bid would tempt them into selling Ross Barkley in January.

The 20-year-old has shone under new management at Goodison Park this season, with his latest noticeable display coming courtesy of a free-kick winner in the 2-1 victory over Swansea City on Sunday.

His performances have impressed some of the Premier League's elite, and England manager Roy Hodgson, with Barkley now considered an almost certainty to go to the World Cup in Brazil next summer.

However, despite reported interest from Chelsea and Manchester United, Martinez has vowed that Barkley will still be with the Toffees after the upcoming transfer window, insisting that he is not for sale at any price.

"Even if we got a Gareth Bale-size valuation we would never even consider it in January," he told reporters. "Ross is an icon for us. He represents everything we are trying to do this season, so even if a stupid offer arrived in January it would never, never affect us.

"It is important for us as a football club to show we are making the right football decisions. There is no question mark over Ross' future, he is in the best moment of his time and is everything we want a player to represent at Everton.

"There is not even a question mark against whether he is going to be here in February or not."

Barkley has scored three goals in 16 top-flight appearances for Everton this season.