Steven Norris, the Conservative candidate for London, has become the interim chairman of rail contracting group Jarvis.

The appointment has led to criticism that he will have a conflict of interest as Jarvis has a one-third stake in the London Underground PPP contractor Tubelines.

But Norris refuted the claims.

"There is an enormous difference between being candidate and being mayor," he said.

"There would only be a conflict if I am elected but in that case I would resign as chairman of Jarvis. I intend to be elected. You'd be surprised. Go and put a bet on."

Interviewed in today's Telegraph, he says: "Ken [Livingstone] is juvenile, whereas I am mature."