British cycling superstar Mark Cavendish is refusing to speculate about his chances ahead of taking the first Olympic gold of the Games in the 250-kilometre road race on Saturday.

The 27-year-old, fresh from the Tour de France, faces the gruelling prospects of nine ascents of Surrey's Box Hill, meaning that victory for any rider is far from certain, despite rivals lauding him as "invincible" and the clear favourite.

Cavendish has lost four kilograms to improve his climbing ability, but said: "If I didn't have a team here, there's no way I could say I'll get over Box Hill nine times alone.

"It's not just Box Hill, it's everything after it. Luckily I've got four of the strongest bike riders in the world around me."

Over a million people are expected to line the route as Cavendish and his four team-mates, Tour winner Bradley Wiggins, Chris Froome, David Millar and Ian Stannard, hope to power to victory in a race which is as much about team tactics as pure power.

Cavendish told reporters: "We're racing in a sport with infinite variables, whether it's luck or someone has a good day, you have a bad day. That's what makes cycling special. It's also what makes you nervous."

The Isle of Man resident is expected to release his signature sprint after the peloton pass the Queen Victoria Memorial.