Mercedes GP would appear to find themselves with a £80million hole in their budget for next season.

Henkel, a German consumer products group, is insisting a three-year sponsorship contract with the team is invalid as the agreement was signed by a former employee without authorisation.

In a statement, Henkel make clear they informed Daimler, the parent company of Mercedes-Benz who bought out Brawn GP last month, of the situation in September.

The company maintain team officials should have been more thorough in their discussions and dealings with the Henkel representative.

Henkel filed legal proceedings against Brawn GP last month.

It is unknown whether the significant loss of funds will have any impact on the team's bid to lure seven-times champion Michael Schumacher out of retirement.

Reports in Germany over the weekend claimed the 40-year-old, who has not competed for three years, was close to agreeing a bumper pay deal with Mercedes worth £20million.

Schumacher and his manager Willi Weber have so far remained tight-lipped, however, the German star's impending move appears to have had one significant obstacle removed.

Schumacher is currently employed as an advisor to Ferrari, the team with whom he won five of his world titles, and is an ambassador for their road car division.

It has always been perceived Schumacher would be unable to carry out the latter duty whilst driving for one of Ferrari's rivals in the sports car market.

Ferrari president Luca di Montezemolo, though, has seemingly made it clear he would not hold Schumacher to his deal, although he has yet to speak to him about his future plans.