Boris Johnson is facing calls to expel the former Tory deputy chief whip from the party after he dramatically quit following a drunken incident.
Chris Pincher, who was responsible for maintaining discipline among Conservative MPs, said he had “embarrassed myself and other people” after having had “far too much” to drink.
The Sun reported that he stood down after assaulting two fellow guests at the Carlton Club – a Tory Party private members’ club in London’s Piccadilly – on Wednesday evening.
However the paper said he would continue to sit as a Tory MP as he was considered to have done the right thing by admitting wrongdoing and resigning.
Labour said it showed the party was “mired in sleaze and scandal” and questioned how Mr Pincher could still be allowed to take the Conservative whip given what had happened.
In May, the Tory MP for Tiverton and Honiton, Neil Parish, resigned his Commons seat altogether after he admitted watching pornography in the Commons chamber.
Labour deputy leader Angela Rayner said: “This latest episode shows how far standards in public life have been degraded on Boris Johnson’s watch.
“Boris Johnson has serious questions to answer about why Chris Pincher was given this role in the first place and how he can remain a Conservative MP.
“The Conservative Party is so mired in sleaze and scandal that it is totally unable to tackle the challenges facing the British people.”
In his resignation letter to the Prime Minister, Mr Pincher apologised for his behaviour, saying it had been “the honour of my life” to have served in the Government.
“Last night I drank far too much. I’ve embarrassed myself and other people which is the last thing I want to do and for that I apologise to you and to those concerned,” he said.
“I think the right thing to do in the circumstances is for me to resign as deputy chief whip. I owe it to you and the people I’ve caused upset to, to do this.
“I want to assure you that you will continue to have my full support from the back benches. It has been the honour of my life to have served in Her Majesty’s Government.”
His departure in such dramatic circumstances is a further blow for the Prime Minister who has been beset with allegations of misconduct over lockdown parties in Downing Street.
The Tamworth MP was appointed alongside chief whip Chris Heaton-Harris last February to shore up support for the Prime Minister amid growing unrest among Tory MPs over the “partygate” disclosures.
It is the second time he has quit the whips office, having resigned as a junior whip in November 2017 following a complaint that he made an unwanted pass at the former Olympic rower and Conservative candidate Alex Story.