The top Tory found watching porn in the Commons is set to remain a Conservative MP for months despite being reported to party whips.
Boris Johnson is under mounting pressure to immediately suspend the MP pending an investigation by an independent body.
Labour leader Keir Starmer has demanded the Tories take immediate action against the still-unnamed MP - rather than wait for an independent probe, which could take months.
But the Prime Minister has insisted “the proper procedures need to be gone through”, in order to “understand the facts”.
The Mirror revealed yesterday that a female minister had caught a Tory MP watching porn on his phone as he sat alongside her in the House of Commons.
The minister told colleagues about the incident, which happened in recent weeks, at a meeting of Tory MPs.
But the Mirror understands Tory whips, who are in charge of party discipline will not investigate or take action themselves.
Instead, they have have told the minister who reported the incident to raise it with Parliament's post-Pestminster watchdog, the Independent Complaints and Grievance Scheme (ICGS).
And a party source confirmed they would not take any action against the MP until after the ICGS probe, or suspend them pending the outcome.
That could mean the accused MP remaining in the Commons for months while the investigation is underway.
It was reported last week that a backlog of 56 MPs, including three Cabinet Members and two Labour Shadow Cabinet members, is under investigation by the ICGS.
None of the MPs have been suspended by their parties.
On Wednesday night, a spokesperson for the whips’ office said: “Following allegations of inappropriate behaviour in the House of Commons, the Chief Whip has asked that this matter be referred to the ICGS.
“Upon the conclusion of any ICGS investigation, the Chief Whip will take appropriate action."
But only witnesses are able to make complaints to the ICGS.
Speaking on the campaign trail in Cumbria, Mr Starmer said there was “nothing wrong with the independent process, but I think the Tory Party, they know who this is, they should take action now.”
Tory Attorney General Suella Braverman said a minority of men in politics “behave like animals” and are bringing Parliament into disrepute with unacceptable behaviour.
She said if the subject of the complaint was found to have been watching pornography it should result in them "no longer holding their privileged position as a Member of Parliament".
And Baroness Nicky Morgan, the former Education Secretary, said she had been "shocked" by the allegation.
She criticised the "male culture" across Parliament, arguing sexism was “not just an issue on Conservative benches” but “across the House”.
Boris Johnson said the allegations are "obviously unacceptable".
Asked by broadcasters during a visit to Burnley whether the parliamentarian would lose the Conservative whip if the allegations are proven, the Prime Minister said: "I think it's obviously unacceptable for anybody to be doing that kind of thing in the workplace.
"It would be the same for any kind of job up and down the country, let's be absolutely clear about that.
"What needs to happen now is that the proper procedures need to be gone through, the independent complaints and grievances procedure needs to be activated and we need to get to understand the facts, but, yeah, that kind of behaviour is clearly totally unacceptable."
Under the ICGS an investigator would examine the case and Parliamentary Commissioner for Standards Kathryn Stone would then make a finding.
In a serious case like this a sanction would normally be decided by the Independent Expert Panel (IEP), which would also hear any appeal.
The IEP could recommend sanctions including expulsion from the Commons or a suspension - which could potentially trigger a by-election under the recall process if it is for longer than 10 sitting days.
Defence Secretary Ben Wallace said "there's no place for pornography in any workplace" and highlighted the need for a cultural change at Westminster.
He told BBC Radio 4's Today programme "I certainly think they should lose the whip" and they could be subject to the recall process.
Mr Wallace told Sky News: "This is a problem, I think, about the overall culture of the House of Commons.
"It is late sitting, long nights with bars, and that very often leads, and it has done for decades, to behavioural challenges."
On Times Radio he said the mix of long hours, high pressure and alcohol could be "poisonous", adding: "My advice to any MP is actually avoid the bars ... finish a day's work and go home."
Meanwhile, a welsh MP told the BBC a member of the Shadow Cabinet had described as a "secret weapon" because "women want to be her friend and men want to sleep with her."
The female MP, who told the BBC she wanted to remain anonymous, said the conversation took place at an event, after she was described as being a "rising star" of her party.
Labour said they would take it "very seriously" if a complaint was made.
