PARIS, Sept 23, 2008 (AFP) - Lewis Hamilton on Tuesday lost his appeal to have his win at the Belgian Grand Prix reinstated after the FIA ruling body confirmed a 25-second sanction against him for cutting a chicane.

Hamilton, the current Formula One championship leader, appeared before the Paris tribunal on Monday and gave a spirited defence of his actions after the British McLaren driver was adjudged to have cut a chicane during a duel with Finnish rival Kimi Raikkonen in the closing laps.

Race officials at Spa-Francorchamps overturned his win and demoted him to third in the belief that he had gained unfair advantage.

The five FIA International Court of Appeal judges in Paris upheld the original decision to hand down a drive-through penalty at the end of the race for a breach of Article 30.3 (a) of the 2008 FIA Formula One Sporting Regulations and Appendix L, Chapter 4, Article 2 (g) of the International Sporting Code.

The hearing ruled that Article 152 of the International Sporting Code states drive-through penalties are 'not susceptible to appeal' and therefore threw out Hamilton's claim.

'Having heard the explanations of the parties the Court has concluded that the appeal is inadmissible,' the FIA judges said.

McLaren's lawyers had tried to press a case that as Hamilton did not take to the pit lane the penalty he received was a time addition rather than a drive-through sanction.

The confirmation of Hamilton's third place means rival Felipe Massa of Ferrari claims a win which slashes the Briton's lead in the drivers' championship to a single point.

In five and a half hours of evidence on Monday Hamilton reiterated his version of events as recorded in a statement given days after the race, saying he had taken the chicane to avoid a collision with Raikkonen.

'I thought I had given back the advantage that I had taken by cutting the chicane. I thought I had done what I needed to,' Hamilton insisted.

McLaren chief executive Martin Whitmarsh and team engineer Phil Prew also appeared before the Paris hearing, but to no avail.

Had he won his appeal Hamilton would have been seven points clear with just four races left to go.

The Briton has 76 points, just one point ahead of Massa, with Poland's Robert Kubica, of BMW Sauber, on third with 58.

The next race is a night extravaganza in Singapore this Sunday.