DEFENCE Secretary Michael Fallon has resigned, admitting that his past behaviour towards women had “fallen below the high standards” expected from someone in his position.

Earlier in the week it was reported that he’d been criticised by journalist Julia Hartley-Brewer for putting his hand on her knee during dinner in 2002.

In his resignation letter, Fallon said: “A number of allegations have surfaced about MPs in recent days, including some about my previous conduct.

“Many of these have been false but I accept that in the past I have fallen below the high standards that we require of the Armed Forces that I have the honour to represent.”

The resignation may force Theresa May to reshuffle her Cabinet sooner than she would have liked.

As the crisis over the sexual harassment scandal at Westminster deepens, May has been accused of ignoring warnings that party whips used evidence about sexual abuse to demand loyalty from MPs.

It came as the Prime Minister wrote to party leaders to ask for a cross-party meeting on Monday to tackle allegations of sexual harassment at Westminster.

Labour MP Lisa Nandy told the Commons yesterday she warned May three years ago about evidence that abuse in parliament was being covered up.

She challenged May on the issue, saying: “Three years ago I brought evidence to her in this House that whips had used information about sexual abuse to demand loyalty from MPs.

“I warned her at the time that unless real action was taken, we risked repeating those injustices again today. On three occasions I asked her to act, and on three occasions she did not.”

May said whips’ offices should “make clear to people that where there are any sexual abuse allegations that could be of a criminal nature that people should go to the police”.

A senior Downing Street source later said at least one of Nandy’s questions appeared to refer to an alleged assault on a child in the 1970s, and that she had been seeking reassurance from May the inquiry into child sexual abuse would be able to look into allegations relating to information held by whips.

Meanwhile, May has ordered an inquiry into claims made against her deputy, Damian Green, after he became the most senior politician yet to be caught up in a tide of allegations and rumours.

The Cabinet Office investigation was launched after activist Kate Maltby, who is three decades younger than the First Secretary of State, told The Times Green “fleetingly” touched her knee during a meeting in a Waterloo pub in 2015, and a year later sent her a “suggestive” text message after she was pictured wearing a corset in the newspaper.

Green, who was sat near May during Prime Minister’s Questions, said any allegation that he made sexual advances to Maltby was “untrue (and) deeply hurtful”.

Tory former minister Anna Soubry said Green should stand down while the allegations are investigated and claimed that in “normal circumstances” he would be suspended.

But Conservative business minister Margot James said she did not think the allegation “warrants anyone’s resignation, temporary or otherwise”.

May had asked Cabinet Secretary Sir Jeremy Heywood to look into the claims against Green.

Asked whether May had full confidence in Green, a Downing Street source said: “I can say she has confidence in the work of the Government. The ministers are getting on with the job.”

Challenged over calls for Green to stand down, the source said: “The key thing is that the investigation is both speedy and thorough, and that is our focus.”

A senior Labour source said there were “clear questions” over whether an inquiry by the Cabinet Secretary could fulfil the need for investigations into alleged wrongdoing by Government ministers to be “robust and independent”.

Labour has launched an independent inquiry into claims that activist Bex Bailey was discouraged by a party official from reporting an alleged rape at a Labour event in 2011 on the grounds it might damage her political career.

Party leader Jeremy Corbyn vowed he would allow “no tolerance” of sexism, harassment or abuse after Bailey spoke out about the party’s failure to support her.

Aged 19 at the time of the alleged attack, she said she felt too scared and ashamed to report it to the police, but eventually summoned up the courage to tell a senior party official.

Number 10 insisted that May had responded to Nandy’s questions, because the role of political parties had been included within the terms of reference of the child sex abuse inquiry.

“The matters raised were dealt with,” the Prime Minister’s official spokesman said.

Meanwhile, two Tory ministers have hit out at what they call false and hurtful allegations of sexual abuse.

Dominic Raab and Rory Stewart both said they had been named on an anonymously compiled list of supposed misdeeds by Conservative MPs, and insisted that the claims were completely untrue.