The inquiry by parliament’s Independent Complaints and Grievances Scheme (ICGS) was set in motion by a formal complaint relating to the former minister’s behaviour at a private members’ club on Wednesday evening.
It is alleged that Mr Pincher groped two men while drunk at the exclusive Carlton Club on London’s Piccadilly. In a letter to Boris Johnson offering his resignation as deputy chief whip, he admitted: “Last night I drank far too much. I’ve embarrassed myself and other people.”
The Tory whip was withdrawn after a day of pressure on the prime minister, who initially attempted to draw a line under the scandal after accepting Mr Pincher’s resignation.
A spokesperson for chief whip Chris Heaton-Harris said: “Having heard that a formal complaint has been made to the ICGS, the prime minister has agreed with the chief whip that the whip should be suspended from Chris Pincher while investigation is ongoing.
“We will not prejudge that investigation. We urge colleagues and the media to respect that process.”
Downing Street announced that Rochester and Strood MP Kelly Tolhurst has been appointed to fill Mr Pincher’s former post as deputy chief whip.