A "warped and degrading culture" - where the abuse of women is accepted and normalised - "thrives in the corridors of power, including Westminster", Jeremy Corbyn is to warn.

MPs who engage in this culture must be held accountable for their actions, the Labour leader will argue.

Mr Corbyn's warning follows reports that four MPs, including a minister, have been caught up in allegations of sexual misconduct at Westminster.

The MPs, two Labour and two Conservative, have been accused of harassing or propositioning young women inappropriately according to The Times.

The Guardian also reported four MPs were involved in allegations of misconduct. It was not clear if the papers are referring to the same individuals.

Theresa May has called the allegations "deeply concerning" and warned that anyone found to have behaved inappropriately would face "serious action".

The Prime Minister also urged anyone with information to contact the authorities.

In a keynote speech, Mr Corbyn will similarly urge women who have suffered such abuse or harassment to report it to authorities, including - if appropriate - the police.

In recent days Mr Corbyn has faced accusations that he was slow to act over misogynistic and homophobic comments by Labour MP Jared O'Mara - including a claim he called a constituent an **"ugly b****"****, which he denies.

Labour suspended the Sheffield Hallam MP in the wake of the comments, while he also resigned from his position on the Commons Women and Equalities Select Committee after it emerged he joked about having an orgy with members of pop group Girls Aloud, claimed Michelle McManus only won Pop Idol "because she was fat" and suggested it would be funny if jazz star Jamie Cullum was "sodomised with his own piano" in 2004.

In an address to the Unite union's Scottish policy conference in Aviemore, Mr Corbyn will say that Labour "will not tolerate any form of discrimination or harassment".

"The problem doesn't stop with those who make unwanted advances on women, it extends to a culture that has tolerated abuse for far too long," he will say.

"It's a warped and degrading culture that also exists and thrives in the corridors of power, including in Westminster."

According to The Times, one of the Labour MPs caught up in the allegations is alleged to have texted a work experience colleague, suggesting there would have been sexual contact had he been younger.

Another Labour MP allegedly sent multiple inappropriate texts "when drunk", including to a researcher in her early 20s, the newspaper said.

The minister involved, who is married, is alleged to have made passes at several women including journalists and aides, according to the paper.

Another married Conservative MP was said to have had affairs with at least two young researchers in the past few years, the paper said.

The Guardian reported there were allegations of inappropriate sexual behaviour by a Conservative former minister while a Labour MP was described as "incredibly predatory".

There were also said be allegations of inappropriate behaviour by a backbench MP during a trip abroad earlier this year while an MP allegedly left a parliamentary delegation after claims about their conduct, the paper said.

Meanwhile it emerged that an attempt by the parliamentary standards watchdog to extend the House of Commons "respect" policy - which protects staff from harassment and bullying - to cover everyone working at the House had been blocked.

In a letter to a friend of a woman who alleged she had been sexually assaulted - seen by The Daily Telegraph - the Parliamentary Commissioner for Standards Kathryn Hudson said it was not "widely understood" that it only covered staff directly employed by the House and did not extend to MPs' staff who they employ themselves.

"I made strong representations at the time for the policy to be extended to all those who work in the House, but this was not agreed and it was restricted to House employees only," she wrote.