As a trade union that represents staff right across the public sector, including those working in Parliament, we regularly hear distressing stories of harassment and abuse from one employee to another. In all walks of life, this kind of behaviour is centred around the power dynamic – not always men against women, and not always an abuse of grade or authority. Not always, but very often.

It has taken years of campaigning and negotiations by unions, including our own, to ensure that practise as well as policy provides an effective route for employees to challenge that power dynamic and call out behaviour ranging from the inappropriate to criminal.

A good organisation doesn’t just have effective sanctions for those who have crossed a line: they foster a culture in which harassment and bullying is actively discouraged. They will have a process in place for raising complaints quickly, providing all parties with an opportunity to have their say, and then it will make reasoned decisions – with proportionate punishment quickly following. Where such a system exists, there can be no hiding place for those who abuse their power – and they will know it. But where it doesn’t, harassers are encouraged to feel they operate in a safe space.

The mother of parliaments is a unique workplace. It’s a mix of elected politicians, employees of the House, staff working for MPs themselves, and an array of journalists, party staff and other organisations. MPs have, for very good reason, independence from the rest of government. Effectively, they are a self-regulatory body. But this means that MPs are quite literally a law unto themselves and, as we have seen time and time again, their ability to self-regulate has been found wanting.

The FDA represents staff who work for Parliament. These staff are not formally part of the civil service, but they are in a very similar situation. For those staff, there are clear and effective policies regarding bullying and harassment between employees of the House. But what happens when such incidents involve an elected MP?

The current rules governing such disputes were brought in in 2014, after pressure from the FDA and other unions about the inadequacy of existing procedures. They are an improvement on the previous rules, but they have a flaw that goes to the heart of why, in the 21st century, we face the problem of harassment and abuse in the first place.

Complaints against MPs cannot be dealt with like those against other employees. The new rules allow for an informal process of settling any complaint, but MPs cannot be compelled to take part. If a complaint is not settled informally, the Parliamentary Commissioner for Standards can be asked to investigate complaints of bullying and harassment made against MPs by employees of the House of Commons. It is only when – or more likely if – a complaint gets referred to the Parliamentary Commissioner that an MP can be compelled to co-operate.

The threshold for investigation by the Parliamentary Commissioner of an MP’s conduct involves a broad definition around standards, and it was never intended for complaints of this nature. There is no right to appeal against any decision that the Commissioner makes. If the Commissioner does find in a complainant’s favour, they may then refer the matter to the separate Committee on Standards.

This Committee may then call the complainant to give evidence on any matter they see fit — despite them already having gone through a previous investigation. If a complaint gets this far, a report will be submitted to the House of Commons and the names of all those directly involved — including the complainant’s – may be published. There is then no appeal against any decision that the Committee makes.

Consider this process from the perspective of an employee making a complaint of sexual harassment. Already feeling vulnerable and victimised, what confidence would you have that justice will prevail or your anonymity will be respected?

As is clear from the House of Cards-style revelations that are leaking out daily, political parties have known about this behaviour for decades but have it seen it simply as valuable material for the Whips’ office. Now imagine that a complaint, perhaps made against an MP with a small majority in the current government, ends up in the hands of fellow MPs on the Committee for Standards.

Electoral maths and partisan interest will play just as significant a role in any decision as the need for justice. This is not wild speculation – we have seen time and time again how issues relating to MPs’ conduct get conflated with party interest.

That a culture of abuse has been allowed to persist in Westminster is indeed a scandal that all parties could have prevented. It is also deeply disappointing that once again, the vast majority of MPs – who are committed public servants – will be tarred with this most unedifying of brushes.

There is no easy solution to this. MPs rightly enjoy a unique status and are accountable to an electorate: they are not simply employees. But if the root cause of this abuse of power is to be addressed, we need a policy that is fit for a 21st Century workplace, with decision-making and oversight independent not only from the MPs themselves, but from the parties that have colluded to protect this culture over decades.

Dave Penman is general secretary of the FDA, the union representing more than 18,000 senior public servants