Real Madrid and Barcelona have joined Chelsea and Manchester City in the race to sign Everton defender John Stones in the summer transfer window. The 21-year-old is regarded as one of the most promising defensive prospects in the country and has attracted interest from clubs across Europe.

The Daily Mail has reported that Rafa Benitez was a huge fan of the player and wanted him at Madrid before being sacked. However, the Spanish giants have maintained their interest and may look to sign him should their transfer ban be repealed. Barcelona are also interested in him, but the £50m ($71m) fee being touted for his services may prove too much for the Catalan club.

In the Premier league, Chelsea are Stones' biggest admirers, having had a £38m ($54m) bid rejected for the player last summer. The Blues' insistence led Stones to hand in a transfer request, but Everton manager Roberto Martinez refused to let him leave, something that has worked in the defender's favour this season, as the defending Champions are struggling in the league.

Manchester City are also interested, with Vincent Kompany struggling to stay fit while Eliaquim Mangala, Nicolas Otamendi and Martin Demichelis have flattered to deceive at the back. City have shown that they are willing to pay top dollar for good English talent as has been the case with Fabian Delph and Raheem Sterling last summer.

Everton have maintained that Stones is not for sale at any price but are likely to be more willing to sell to a Spanish club than anyone in England's top flight when an offer comes their way. The defender is expected to make the England squad and travel to France for the European Championships later this year.

The defender has been earmarked as a likely replacement for John Terry while Barcelona centre-back Gerard Pique has waxed lyrical over the player's defensive nous in a recent interview.