John Stones
John Stones has been subject of intense speculation regarding his futureGetty Images

Chelsea have received a huge boost to their hopes of securing the services of Everton defender John Stones after the 21-year-old England international handed in a transfer request. Jose Mourinho has earmarked the signing of the English starlet as a priority before the end of the current transfer window to finish the summer overhaul of his squad, after having already completed deals for Radamel Falcao, Asmir Begovic, Pedro, Abdul Baba Rahman and young trio Nathan, Kenedy and Danilo Pantic.

Roberto Martinez, however, has reiterated that the centre-back is to remain at Goodison Park this season after the club reportedly rejected three separate bids from the Blues – including one worth around £30m (€47.3m). The Everton manager has warned Chelsea that the Toffees will not sell Stones, even if the England defender hands in a transfer request.

"No. When you got a long-term contract those things don't change at all. If someone comes in from nowhere and puts in a transfer request that is a different situation," Martinez said, as quoted by the Daily Mail. "In a saga of I-don't-know how many weeks now, we are very clear. I speak to John every day. As a footballer, unless two clubs reach an agreement, you can't do anything."

But The Independent recently reported that Everton would eventually consider Stones' departure should Mourinho's side submit a fourth bid of £40m. Stones himself has now added fuel to the speculations with the BBC reporting he has handed in a formal transfer request to force the proposed move to Stamford Bridge.

Mourinho has John Terry, Gary Cahill and Kurt Zouma in his central defensive ranks. But after the trio suffered a struggling start to the campaign, conceding eight goals in three Premier League games, he is ready to break the bank to secure Stones as a long-term replacement for Terry.