LONDON (AFP) - Five-time Olympic champion Bradley Wiggins embarked upon his final event on British soil on the opening day of the London Six Day on Tuesday, his first competitive appearance since revelations he used a banned substance.

The 36-year-old, who became Britain's first Tour de France champion in 2012 and is due to retire next month, was moved to defend himself after leaks of his medical records by presumed Russian hackers revealed he was granted therapeutic use exemptions (TUEs) for a steroid.

"It's just good to get back on the bike. I love riding the track," said Wiggins, who received a warm welcome from the crowd at Lee Valley VeloPark.

He has been forced to answer uncomfortable questions about his stance on doping ever since cyber hackers the Fancy Bears revealed his use of the banned triamcinolone last month.

Wiggins and Team Sky principal Dave Brailsford have strenuously denied wrongdoing over the use of the drug, which has been linked to doping offences in the sport.

Wiggins had three TUEs for the substance approved by world cycling's governing body the UCI to treat a pollen allergy.

There is no suggestion he broke any rules. UK Anti-Doping is investigating allegations of wrongdoing after reports a package was delivered to Team Sky during the 2011 Criterium du Dauphine, which Wiggins won.

Sky, British Cycling and Wiggins are co-operating with the probe. Wiggins will bow out at next month's Six Day in Ghent, the Belgian city where he was born.