Chris Evans has stepped down as Top Gear presenter after saying his best shot was "not enough".

The TV and radio presenter said he was stepping down after just one series, amidst flagging ratings. Top Gear's audience fell to a new low of fewer than two million viewers as the series stalled again in the ratings on Sunday.

Evans tweeted: "Stepping down from Top Gear. Gave it my best shot but sometimes that's not enough. The team are beyond brilliant, I wish them all the best."

He added: "Full steam ahead then with Radio 2, CarFest, Children In Need, 500 Words and whatever else we can dream up in the future."

In a statement, he said: "I have never worked with a more committed and driven team than the team I have worked with over the last 12 months. I feel like my standing aside is the single best thing I can now do to help the cause.

"I remain a huge fan of the show, always have been, always will be. I will continue to focus on my radio show and the allied events that it encompasses."

Mark Linsey, director of BBC Studio's, said: "Chris is stepping down from his duties on Top Gear. He says he gave it his best shot doing everything he could to make the show a success.

"He firmly believes that the right people remain, on both the production team and presenting team, to take the show forward and make it the hit we want it to be."