London: A “warped and degrading culture” of sexual harassment and abuse exists and thrives in Westminster, the Labour leader will say.

In a speech to members of the Unite union in Scotland, Jeremy Corbyn will urge anyone who has experienced harassment or abuse to come forward.

He will warn MPs who have engaged in sexually inappropriate behaviour that they must be held to account for their actions.

The comments come as the Guardian reported that senior MPs have raised complaints that allegations of sexual harassment are still not being taken seriously enough by their parties and whips despite years of warnings.

MPs made their fears known to their parties after the Labour MP Jared O’Mara was suspended over allegations of misogynistic abuse, and parliamentary staff aired allegations of sexual harassment and assault on a private WhatsApp group.

The decision by women in Westminster to share information comes in a new atmosphere of open revulsion at sexual misconduct following the allegations of assault and rape against Hollywood producer Harvey Weinstein.

“Sexual abuse and abusive treatment of women by men is not confined to any one industry, workplace or institution,” Corbyn will say in Aviemore. “It is rooted in unequal power relationships that treat women as subordinate to men, and a culture where the abuse of women has often been accepted and normalised.

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

The Labour leader will urge anyone with complaints to come forward to their party organisations, the Commons authorities or police.

The Guardian has been made aware of a number of complaints against MPs and other senior figures that have not yet been made public, including: Allegations about inappropriate sexual behaviour of a Conservative former minister; A Labour MP described as “incredibly predatory”; A backbencher where an allegation of inappropriate behaviour was made on a trip abroad earlier this year; An MP who allegedly left a parliamentary delegation after allegations about their conduct.

Both Corbyn and the prime minister, Theresa May, called on Friday for any staff members who have experienced sexual harassment or abuse to contact the House of Commons authorities or police to make formal reports.