The sell-on clause is understood to be structured and complicated rather than a lump sum percentage, but the Reds could net more than £5million. The fee is the highest ever paid for an Englishman. 

The 22-year-old from Thurlstone played 28 games for the Reds, after coming through the Oakwell academy, then moved for Everton in January 2013 for a fee rising to £3million. 

Stones has played 77 Premier League games for the Toffees and has made ten England caps.