Chris Evans, who headed the Top Gear reboot after the departure of Jeremy Clarkson, has stepped down from the show. Evans was brought in alongside Matt LeBlanc and host of other new faces to fill the positions left by Clarkson, James May, and Richard Hammond. The first series of the show had poor ratings, with fewer than 2 million viewers tuning into its series finale this weekend — lower than any episode helmed by Clarkson.

Evans is the subject of a sexual assault investigation

According to The Telegraph, Evans is also being investigated by the police for allegations of sexual assault. The paper reports that Evans is accused of grabbing the breasts of a female colleague in the 1990s. The Metropolitan police confirmed the investigation, adding: "There have been no arrests and no person has been interviewed under caution." Evans has previously denied these and other claims (including that he repeatedly exposed himself to colleagues), describing them as a "witch hunt."

Evans announced the news in a tweet, saying he'd given the show his "best shot" but sometimes that wasn't enough.

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. — Chris Evans (@achrisevans) July 4, 2016

Full steam ahead then with Radio 2, CarFest, Children In Need, 500 Words and whatever else we can dream up in the future. — Chris Evans (@achrisevans) July 4, 2016

In a press statement, Evans added: "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."

Clarkson, May, and Hammond, have meanwhile moved to Amazon for a new motoring show titled The Grand Tour. Amazon has already ordered 36 episodes, with the show expected to air some time later this year. Clarkson was originally fired from the BBC's Top Gear after assaulting a member of the production team.

Updated Monday July 4th, 10:51AM ET: Added new information about a police investigation into allegations of sexual assault and a statement from Evans.