MPs are ignoring training to stamp out bullying and sexual harassment of their staff, which remains at an “unacceptable” level, a damning report finds today.

Just 34 out of the 650 MPs have joined a course to enforce a new “behaviour code”, introduced one year ago, says a QC asked to investigate the “Pestminster” scandal.

Her alarming report highlights how MPs routinely “shout at, demean, belittle and humiliate their staff on a regular basis, often in public”.

“The constant ‘drip, drip’, as more than one contributor put it, eats away at the employee’s self-confidence until they become anxious, exhausted and ill, incapable of performing their job and (often following a period of sick leave) resign or are dismissed,” Ms White warned.

“Well over half of the people who contributed to this inquiry described suffering significant mental and/or physical illness as a result of this type of bullying behaviour.

“Sexual harassment is also a problem, with staff being subject to unwanted sexual advances, often accompanied by touching, sometimes forceful.”

Leader of the Commons Mel Stride announced that MPs will vote next Wednesday on whether to open up a new grievance system to cover allegations dating back before the 2017 election and complaints made by people who are no longer employed in parliament.

Helplines set up last year to deal with complaints of harassment and sexual misconduct since 2017 have received some 783 calls and emails over the past 12 months, leading to as many as 42 investigations being opened.

A vote to extend the scope of the system might open the door to complaints by former staff of Speaker John Bercow who have gone public with bullying allegations, which he denies. An inquiry into the Speaker was blocked last year.

Ms White was critical of the current bar on dealing with the grievances of former staff, who she said were “the most likely to bring a complaint”.

“This limitation must be removed so that they have the opportunity to hold MPs to account,” her report states.

Mr Bercow chaired a meeting of the House of Commons Commission a fortnight ago which cleared the way for the MPs’ vote to take place.

The so-called “Pestminster’ scandal broke in late 2017, revealing widespread allegations of inappropriate behaviour in the wake of the Harvey Weinstein scandal in the US.

A dossier, compiled by Tory aides, included accusations of a minister “handsy with women at parties”. Michael Fallon, the defence secretary, resigned after admitting inappropriately touching the knee of a journalist.

A “Valuing Everyone” training course was set up in July 2018, but only 34 MPs – and just 135 out of 3,200 MPs’ staff – have attended, or been booked onto, it.

In her report, Ms White concludes that little has changed in the past year, writing: “There is an unacceptable level of sexual ‘banter’ and unwelcome discussion of intimate sexual details.

“The majority of contributors described being bullied and harassed by their MP employer. A much smaller number described behaviour of fellow staff members but in some of those cases spoke also of their MP employer failing appropriately to address complaints.”

Shockingly, the QC finds that the “worst offenders are well known”, but “other than the odd ‘quiet word’ from a fellow MP or the relevant whips office, action has rarely been taken to address their behaviour”.

“In the words of one contributor, there has been a ‘general disregard for the dignity, wellbeing and employment rights' of MPs’ staff,” she concludes.

The House of Commons Commission, in charge of administration, pledged to look “urgently at the recommendation” when it meets on Monday.

“We condemn bullying and harassment of MPs’ staff and offer our full support to anyone in the parliamentary community who has suffered in this way,” it said.

Speaker John Bercow (PA)

Mr Stride said: “Any one person – and I say this as the father of three daughters – who is put into the position where they are preyed upon by somebody in authority, that is one way too many. And that needs to be stamped out, there needs to be absolutely no place for that.”

Treasury minister Liz Truss called for a “root and branch” review of the way the House of Commons operates in the wake of the White Report.

She told a Westminster lunch: “I’m a big supporter of modernisation of the Houses of Parliament.

“When I was first elected as an MP, I campaigned for better hours. I still think it is an antediluvian organisation with many archaic practices and we need to modernise things like staff recruitment, staff management.

“That applies to everybody, including the Speaker of the house. It is simply not good enough in the 21st century, where we are going around lecturing other employers about how they deal with sexism, how they deal with representation, how they deal with bullying, but not to get our own house in order.”