England U-21s star Ravel Morrison could be set to leave West Ham in a shock £20m move after details of a get-out clause in his contract emerged.

BT Sport has learned that a number of Premier League clubs, and a top European side, have already made inquiries, with West Ham ready to consider bids above the £18m minimum release fee written into his complex contract.

Morrison is one of the most gifted players in the West Ham squad, but boss Sam Allardyce may be forced into selling one of his brightest stars, despite needing all the quality possible for a potential relegation battle.

The 20-year-old has 18 months left on his current contract but West Ham fear the numerous clauses – such as a stipulation that any direct offers for £10m or more made for him must instantly trigger a pay rise to £60,000-a-week – would make renewing a new deal extremely unlikely.

Any £10m offers for Morrison, who was signed from Manchester United for £650,000 (rising by £25,000 per appearance) would need to be paid immediately in full, but the Hammers would accept instalments on offers above £15m.

If West Ham opted to cash in and offload Morrison now, knowing they might not be able to resolve the complex clauses in his deal, then owners David Gold and David Sullivan would re-invest in new signings.

The owners are committed to buying one, possibly two, new strikers and are also in the market for a central defender, with one more player joining the club if Morrison was to be sold.

Morrison's complex contract

  • £18m - release clause
  • £60,000 - amount Morrison's wages will rise to after outright £10m bid
  • 18 - months left on his deal
  • £15m - amount West Ham would consider for an installments-only bid
  • £25,000 - amount paid to Manchester United for each appearance

The Hammers have made enquiries about Everton pair Johnny Heitinga and striker Nikica Jelavic, who have both been told they can leave Goodison Park but the Hammers have already baulked at the £6m asking price for Jelavic. They would, however, be able to take him on loan with a view to a permanent deal in the summer.

West Ham are missing record signing Andy Carroll, key defender Winston Reid, winger Stewart Downing and Ricardo Vaz Te, while James Tomkins limped out of Saturday’s match.

A striker is a priority and they were knocked back when enquiring about Southampton’s Rickie Lambert, the Saints insisting he is not for sale unless they buy a new striker.

Asamoah Gyan is a “long shot” according to Hammers insiders and a decision rests with his club in the United Arab Emirates, Al Ain.

Allardyce admitted that the Ghana international was on his radar, having asked to take the striker on loan .