German sportswear giant Adidas will end its sponsorship of the T-Mobile cycling team at the end of 2008 at the latest, and perhaps earlier, after a raft of recent doping controversies that have rocked the team.

Adidas said its contract would be not be extended beyond its 2008 expiration date and added that the company was seeking to terminate it with immediate effect.

"This has been relayed to T-Mobile officials this week," said Adidas in a statement. "It's the result of the revelations of the last few days."

Adidas was referring to the doping confessions of rider Patrik Sinkewitz, sacked by T-Mobile in July during this year's Tour de France after he was discovered to have had abnormal levels of testosterone in his blood during a pre-race drug test.

The 27-year-old appeared in front of a German cycling federation (BDR) disciplinary committee two weeks ago and gave five hours of evidence in a bid to have his expected two-year ban reduced.

But his revelations, having confessed to blood doping and being administered the banned blood booster EPO by two former team doctors up until 2006, have done nothing for the relationship between T-Mobile and its sponsors.

"Adidas condemns doping in any form and will in the future remain faithful to its principle of terminating contracts with sportsmen who are using dope," said the German company’s statement.

There is some question whether Deutsche Telekom, which has sponsored the German cycling team since 1990, will remain on board as main sponsor.

The company spends more than 10 million euros a year on the team, an investment first tarnished when 1997 Tour winner Jan Ullrich was sacked in 2006 over suspicions that he was implicated in a major Spanish doping scandal.

The relationship between the cycling team and its sponsor was damaged further when several former riders confessed to taking EPO earlier this year.

Then Ukrainian Serhiy Honchar was sacked in June for an abnormal blood test.

Sinkewitz's July dismissal followed Deutsche Telekom's threat to end its sponsorship of the team in the event of more doping confessions.