The Tory MP under investigation for allegedly groping two men said he is seeking “professional medical support” and hopes to return to his duties “as soon as possible”.

Chris Pincher said on Saturday he is “truly sorry” and vowed to fully co-operate with the inquiry into his drunken behaviour at a private members’ club in London.

The MP for Tamworth in Staffordshire resigned from his Government role after the allegations emerged, and Boris Johnson bowed to pressure to remove the Conservative whip.

But the Prime Minister was facing fresh questions over why he made him deputy chief whip despite a slew of allegations, with Dominic Cummings claiming Mr Johnson had jokingly referred to him as “Pincher by name, pincher by nature”.

Now sitting as an independent, Mr Pincher is battling to remain in the House of Commons despite opponents saying his position is untenable.

In a statement, he said: “I respect the Prime Minister’s decision to suspend the whip whilst an inquiry is under way, and I will co-operate fully with it.

“As I told the Prime Minister, I drank far too much on Wednesday night, embarrassing myself and others, and I am truly sorry for the upset I caused.

“The stresses of the last few days, coming on top of those over the last several months, have made me accept that I will benefit from professional medical support.

“I am in the process of seeking that now, and I hope to be able to return to my constituency duties as soon as possible.”

Critics in Westminster are unlikely to be calmed by the statement from the man who resigned as deputy chief whip when reports of his latest behaviour first emerged.

Neil Parish, the former Conservative MP pressured to resign from the Commons after watching porn in Parliament, has accused No 10 of “double standards”.

Tory backbencher Andrew Bridgen echoed the sentiment, suggesting Mr Pincher was being treated differently because he is an “arch-loyalist” to the Prime Minister.

He said claims about Mr Pincher had been “swirling around Westminster for years” and suggested Downing Street would surely have been aware of them.

Mr Cummings, the Prime Minister’s chief aide turned critic-in-chief, accused Mr Johnson of “lying again” about his knowledge of Mr Pincher’s behaviour before giving him the whips job.

He said Mr Johnson referred to the MP “laughingly in No 10 as ‘Pincher by name, pincher by nature’ long before appointing him” in February.

A No 10 spokesman previously acknowledged there had been concerns about Mr Pincher before his appointment, but insisted Mr Johnson “was not aware of any specific allegations”.

On Saturday, Downing Street did not deny Mr Cummings’ claim, which if true suggests the Prime Minister may have been aware of more than the spokesman acknowledged.

Mr Johnson had been resisting calls to suspend the MP from the party until the Independent Complaints and Grievance Scheme (ICGS) launched an investigation after receiving a formal complaint.

The Prime Minister spoke to several individuals on Friday, including a Tory MP who was with one of the men allegedly groped by Mr Pincher, a Downing Street source said.

“The account given was sufficiently disturbing to make the PM feel more troubled by all this,” the source told the PA news agency.

A stream of further claims were levelled against Mr Pincher, with The Times reporting a young Tory activist receiving an unwanted sexual advance last year.

The activist said the MP put his hand on his knee and told him he would “go far in the party” at a Conservative conference event last year.

Mr Pincher’s lawyers told the newspaper he firmly denies the allegation, which mirrors a complaint that led to the MP’s resignation from the whips’ office for the first time in 2017.

Former Olympic rower and Conservative candidate Alex Story alleged Mr Pincher touched him while making an unwanted pass and using similar language.

Mr Pincher was reinstated two months later as a senior whip by Theresa May after referring himself to both the police and the Conservative Party complaints procedure.

Boris JohnsonBoris Johnson has been told to expel Mr Pincher from the Tory Party (John Sibley/PA)

The latest allegations came after the Conservative Party was hit by a series of scandals relating to sexual misconduct.

In May, Mr Parish quit as MP for Tiverton and Honiton after admitting viewing pornography in the Commons chamber, while the previous month Wakefield MP Imran Ahmad Khan was jailed for 18 months for sexually assaulting a 15-year-old boy.

In both cases, the Conservatives lost the ensuing by-elections.

A third unnamed Conservative MP has been told by whips to stay away from Parliament after being arrested on suspicion of rape and other offences.