Millar was banned for two years

The sport has suffered several knocks to its image again this year, chief among them the positive test for Tour de France winner Floyd Landis.

But Millar says the Landis case in particular has made cycling realise it has a "fundamental cultural problem".

"It's waking up the sponsors and the team management to the problems they're facing," said the Scot. "They've had their heads in the sand for too long."

Landis failed a test for testosterone following his dramatic win on stage 17 in this year's Tour de France.

The 30-year-old American has protested his innocence, claiming there were a host of inconsistencies in the paperwork and results provided by the laboratory who carried out the test.

But Millar says that, regardless of the outcome of that case, cycling now faces a real fight to rescue its credibility.

"Our sport is at the bottom of the barrel at the moment on a professional level and perhaps that's where we need to be to climb back out," he told Radio Five Live.

Millar is no stranger to controversy himself.

The Scot, 29, was banned for two years after confessing to the use of blood booster erythropoietin in 2004.