By Editor Wayne Veysey | Former Evening Standard, Press Association and Goal chief correspondent with 17 years experience of breaking big stories, including exclusives like this

Follow me on Twitter @footyinsider247

Chelsea and Manchester United have joined Manchester City in the race to sign Jamie Vardy this month, Football Insider sources understand.

The Premier League big-hitters have asked to be kept informed about Vardy’s situation despite Leicester insisting he is not for sale.

Football Insider revealed last month that City are closely monitoring the Premier League’s top scorer as they look at ways of beefing up their strike force in the winter window.

Chelsea and United are also in the market for a new front man as they bid to improve on disappointing first halves of the campaign.

Chelsea’s back-up strikers Loic Remy and Radamel Falcao have only scored two Premier League goals between them, and the Londoners will allow one of them to leave in January if they can secure a proven replacement.

United have also struggled for goals this season, with first-choice pair Anthony Martial and Wayne Rooney scoring just eight league goals in total.

Club chiefs, led by director of football Txiki Begiristain and manager Manuel Pellegrini, decided to rely on just two senior strikers this season in Sergio Aguero and Wilfried Bony after selling Edin Dzeko to Roma. But they are considering a re-think due to Aguero’s injury problems and concerns about Wilfried Bony’s capacity to stretch top defenders.

Vardy has been one of the key players in Leicester’s climb to the Premier League summit, striking 15 times in the competition this season to top the scoring charts alongside Everton’s Romelu Lukaku.

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The 28-year-old wrote his name into the history books by scoring in a record 11 consecutive Premier League games for the east Midlands club and has been one of the outstanding players in the top flight this season.

He is likely to be rated well beyond £20million by Leicester, who have said they will not sell any of their players in January.

As revealed by Football Insider on Wednesday, Leicester came close to selling Vardy to Sheffield Wednesday in the summer for £5million.

The terms of a deal had been agreed between the two clubs, and Sheffield-born Vardy had given it the green light, but the Championship club’s new Thai owners pulled the plug at the last minute.

Vardy has subsequently taken his game to a new level and he is being eyed as a possible option by the leading clubs.