Everton defender John Stones has handed in a transfer request in an attempt to persuade his club to sell him to Chelsea, according to reports on Tuesday.

Stones is Chelsea manager Jose Mourinho's top target as he seeks to bolster his defensive options, but Everton have rejected three offers for the England international and he has now taken matters into his own hands.

After Chelsea's latest bid of £30 million ($47 million) was snubbed by the Goodison Park outfit, Stones is widely reported to have formally expressed his desire to leave before training on Tuesday.

However, Everton have been resolute in their determination to hang on to the 21-year-old and manager Roberto Martinez has insisted throughout the saga the centre-back is not for sale.

Martinez refused to even discuss what the club's response would be should the player hand in a transfer request when he was asked about it on Tuesday.

"There is nothing to comment on that," he said.

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"Once more, it is always the same question and always the same answer."

But despite Martinez's determination to keep Stones, who joined Everton from Barnsley for £3 million in January 2013, the youngster is convinced he can persuade the club to sell him before the September 1 transfer deadline.

If he does the Premier League champions, Stones will add much-needed depth to Chelsea's central defence after the struggles of John Terry and Gary Cahill this season.