Spanish operator Codere that runs bingo clubs, casinos and betting shops has challenged Bwin in court over the Real Madrid shirt sponsorship.

The application to the Madrid Commercial Court states that Bwin’s advertising contravenes competition laws in the country. Codere claims “Bwin carries out unfair advertising, competing unfairly in Spain with authorised operators such as Codere”.

Gaming giant Bwin's has seen their brand advertised on the football shirts since start of the 2007-08 season, and in 2009 the two parties agreed an extension through to 2013 reportedly worth more than 20 million Euros per year.

Other online gaming operators that have agreed sponsorship deals have run into legal problems in countries such as France and Germany in recent years, although the legislation against such firms is gradually being relaxed.

“Authorised gambling operators in Spain are not permitted to advertise or may only do so subject to stringent restrictions and after obtaining authorisation from the authority,” read a statement from Codere.

“Neither are authorised operators able to operate games through the internet, although they have the necessary technology and expertise to do so, since these games are prohibited in Spain and in some cases may be activities liable for prosecution in the context of criminal law,” the statement added.