House of Commons staff will have “little other choice” than to go on strike unless tough action is taken to address the culture of bullying and sexual harassment, union leaders have warned.

Amy Leversidge, assistant general secretary of the FDA – which represents civil servants, said workers had been “pushed to breaking point” and the organisation would “support members” if they decided to stage a walkout.

It follows a probe by High Court judge Dame Laura Cox that lifted the lid on a toxic environment in Westminster.

Failure by the House of Commons Commission, which meets to discuss how to respond to the report on Wednesday, to back the “full and immediate” implementation of the recommendations would leave staff with “little other choice” than to strike, Ms Leversidge said.

She told The Sunday Times: “Industrial action is always a last resort and nobody would take the decision lightly, especially Commons staff, who are immensely loyal to Parliament.”

It comes after a former Commons clerk said Commons 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.

Conservative MPs have called for Mr Bercow to quit, but senior Labour figures said keeping him in post to deal with Brexit legislation was top priority.

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.

“The House of Commons Commission will have a large role in what happens next,” she told HuffPost UK.

“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).”

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.”

A House of Commons spokeswoman said: “We thank Dame Laura Cox for her report. Bullying and harassment have no place in the House of Commons. We recognise the impact of bullying and harassment described in the report and plan to work closely with staff, unions and Workplace Equality Networks to address these issues.

“Staff must be confident that unacceptable behaviour will be dealt with seriously, independently and with effective sanctions.

“Urgent work has already been undertaken to improve internal processes – including the introduction of new confidential support services and helplines run by external, independent specialist providers.

“The findings of this report will be discussed at a House of Commons Commission meeting on Wednesday.”