John Stones to Chelsea: Everton unimpressed by £20m bid but Blues remain confident of signing England defender

Mourinho identified 21-year-old as man he wants to strengthen defensive options

Ivica Olic of VfL Wolfsburg crosses the ball as John Stones of Everton closes in during a UEFA Europa League Group H match (Getty)

Chelsea are confident they will succeed in signing Everton defender John Stones, despite having an opening £20m offer turned down.

Manager Jose Mourinho has identified 21-year-old Stones as the man he wants to strengthen his defensive options next season and also be the long-term successor to captain John Terry.

Chelsea are expected to come back with a higher offer worth £26m, even though Everton insist he is not for sale. However, it is believed Everton will change their stance if Chelsea are prepared to pay £35m and make Stones the most expensive defender in Premier League history. A compromise deal between those two figures is the likeliest outcome.

Eliaquim Mangala joined Manchester City from Porto for £32m last year, while Rio Ferdinand is still the costliest English centre-half, dating from his £30m switch from Leeds to Manchester United in 2002.

At this stage, Chelsea are believed to be unwilling to pay more than £26m, so reaching an agreement will not be easy. However, the champions remain hopeful they will be able to get their man before their opening Premier League game, against Swansea, on 8 August.

Stones has enjoyed a meteoric rise since joining Everton from Barnsley for £3m in January 2013. He was rewarded with a new five-year contract last August and given a pay rise to £30,000-week, but Chelsea can treble his salary.

Stones has already won four England caps and is tipped to become a mainstay of the national side.

As a ball-playing centre-half, Stones – who played only 25 times for Barnsley, his home-town club, before being becoming David Moyes’ final signing for Everton – would be a natural fit for Chelsea.

Mourinho is a huge admirer and wants to add him to his squad now, even though Chelsea boasted the best defensive record on the way to winning the title last season.

Terry and Gary Cahill were his first-choice pairing, while youngster Kurt Zouma and right-back Branislav Ivanovic are back-up options.

But with Terry turning 35 in December, Chelsea are aware they need to have a successor in place for when his career eventually comes to an end.

Chelsea captain John Terry (GETTY IMAGES)

Significantly, Terry spoke of his admiration for Stones in an interview earlier this summer.

While on tour with Everton in Singapore, Stones insisted he was not looking to leave Goodison Park. He said: “I am very happy at Everton. My aim right now is to try to nail down a regular spot in this Everton team and hopefully that will take care of playing for England. I have to keep learning from the likes of Phil Jagielka and keep progressing at this club.”

Chelsea believe that a big-money offer will change his mind. howeer.

Manchester United are also admirers of Stones, but Everton are puzzled by reports they are on the brink of signing United defender Jonny Evans, as a stand-alone deal or as part of a package for Stones.