A former Commons clerk has said Speaker John Bercow called her a “little girl” when he could not find the envelope he was looking for.
Libby Bradshaw said Parliament is haemorrhaging talent as a result of the way staff are treated.
She said calls for change set out in a report into bullying and harassment in the Commons are in “danger of being drowned by politics again”.
In an article for HuffPost UK, Ms Bradshaw, who worked in Westminster for 12 years, wrote: “There has been a haemorrhage of talent from Parliament because of this issue alone and some of the brightest, most capable people I worked with are no longer there because of the treatment they received.
“This is not only bad for public service, but it turns the patriarchy into a self-fulfilling prophecy in one of the most high-profile organisations in the country.
“The House of Commons Commission will have a large role in what happens next.
“The Commission is made up of some of these senior managers along with the Speaker who, when he was just a regular backbencher, once screamed at me and called me a ‘little girl’ simply because he had been unable to find an envelope (which was exactly where I said it was, for the record).”
Conservative MPs called for Mr Bercow to quit after a probe by High Court judge Dame Laura Cox lifted the lid on a toxic environment in Westminster.
But Labour’s Dame Margaret Beckett faced criticism when she said she believed the constitutional future of the country as a result of Brexit “trumps bad behaviour”.
Shadow foreign secretary Emily Thornberry insisted it was “absolutely not the time to be changing Speaker” and pointed to uncertainty over what would happen next with Brexit.
Dame Laura’s report found a culture of “deference, subservience, acquiescence and silence” had allowed the mistreatment of staff in the House of Commons to thrive.
She said it was “difficult to envisage” how the reforms needed could be delivered under the current senior House administration.
Ms Bradshaw, who contributed to the Cox Report, said she knew of dozens of former colleagues who had been bullied, assaulted and abused while working in Parliament.
She added: “The Cox Report should be a pivotal moment in Parliament’s evolution into a modern workplace and those of us that contributed to the inquiry felt relieved and vindicated that we had finally been believed when we read the report and recommendations.
“But there is already talk that the report could get kicked into the long grass and the tribal warfare surrounding the Speaker, and Brexit, have meant that this issue that has affected so many lives and careers is in danger of being drowned by politics again.”
A spokeswoman for Mr Bercow said: “The Speaker has absolutely no recollection of this alleged incident - and it’s not, in his experience, the sort of statement he would make.”