Fifteen top European soccer clubs are under pressure to renew their shirt sponsorships by next season as contracts expire and the recession shows no sign of abating. "In times of financial hardship, firms will naturally look for ways to cut costs, and sponsorship of sporting events, including football shirts, seems a natural and easy target," Chris Brooks, professor of finance and director of research at ICMA Centre, University of Reading, told Reuters.

Although many experts consider it unlikely that top clubs such as Manchester United will be unable to sign lucrative new deals, smaller clubs may have to accept lower income.

"Even if football clubs continue to attract some degree of sponsorship it is most likely that future arrangements will be less lucrative for the clubs," said Joe McLean, a soccer finance expert with accountants Grant Thornton.

West Ham United signed an 18-month contract with online betting company SBOBET that has half the value of their previous deal.

Their Premier League rivals West Bromwich Albion have not been able to agree a shirt deal this term, while six Primera Liga clubs started the season with no shirt sponsor.

"Outside the upper echelons of the game, clubs are in for a bumpy ride over the next 18 months and will have to adjust their expectations if they are to successfully secure shirt sponsorship deals," explained Simon Chadwick, professor of Sports Business Strategy and Marketing at Coventry University.