Jeremy Corbyn wants an independent investigation into allegations of bullying by Commons Speaker John Bercow, his spokesman has revealed.

The Labour leader’s tough stance came as he also slapped down his own MPs for suggesting that the need to stop a hard Brexit “trumps bad behaviour” in Parliament.

Bercow strongly denies claims that he shouted at and bullied former staff in his office, even though one has accused him of leaving her with post-traumatic stress disorder (PTSD). Senior clerk Kate Emms left his office after working for him for less than a year.

A new report by QC Dame Laura Cox this week found that a culture of “deference, subservience, acquiescence and silence” had allowed the mistreatment of staff in the House of Commons to thrive.

Corbyn’s spokesman said: “Obviously the allegations and evidence provided in the Cox report are extremely concerning.

“In relation to the Speaker, any allegations need to be investigated against whoever they are made about.

“It’s not in Jeremy’s or anyone else’s scope to comment on the detail of allegations they haven’t seen. But his very clear view is that any allegation should be properly investigated.”

Earlier this year, the Commons standards committee voted by three MPs to two against allowing Parliament’s watchdog to investigate the claims against Bercow.

The controversy highlighted the gap in current Commons procedures which fails to allow ‘historic’ complaints made against MPs.

Dame Laura’s report this week explicitly called for the rules to be changed to allow such cases to be heard, as well as demanded a change in the “current senior House administration”, a veiled reference to Bercow himself.

Asked if Corbyn supported the recommendation, his spokesman said: “The issue of historic allegations, we have been pressing for that to be properly addressed before.” 

The Labour leader also made clear that he disagreed with Labour MPs who have suggested the Speaker cannot be replaced in coming months because he was needed during the Parliamentary process on Brexit.

Shadow Foreign Secretary Emily Thornberry, party grandee Dame Margaret Beckett, and former Cabinet minister Ben Bradshaw have all suggested that Bercow should be kept in post to oversee the crunch Commons votes on the UK’s plans to quit the EU.

“I think this is absolutely not the time to be changing Speaker,” Thornberry said this week.

“We don’t know, for example, with regard to Brexit, what is going to happen, whether there’s going to be, technically, an amendable motion or not, whether it’s going to be the Speaker’s discretion whether it is. We do need to have all hands to the deck at the moment.”

Beckett told the BBC: “If it comes to the constitutional future of this country, the most difficult decision we have made, not since the war but possibly, certainly in all our lifetimes, hundreds of years, yes it trumps bad behaviour.” 

But Corbyn’s spokesman said his firm view was that the issues were “entirely separate” and the focus should instead be on holding MPs to account and rooting out bullying, harassment and abuse.

“Jeremy’s view is that the issue of Brexit and the issue of bullying and harassment and abuse in Parliament and any workplace are entirely separate. And shouldn’t be confused in any way.

“Jeremy’s view is absolutely clear. Jeremy described what’s been uncovered as a depraved and warped culture which needs to be addressed in a comprehensive way.”

Asked on Wednesday at a Commons Press Gallery lunch whether Brexit was more important than tackling bullying in the Commons, Shadow Chancellor John McDonnell said: “One doesn’t shade out the other.”

Corbyn’s spokesman added that the Labour leader was not expressing a view on whether the Speaker should be replaced. Bercow has told friends he plans to step down next year.

“The matter of [who is] the Speaker is an issue for MPs not for leaders of political parties,” the spokesman said.

The civil servants union, the First Division Association, has condemned Thornberry for putting “party politics before people”.

FDA deputy Amy Leversidge blogged for HuffPost UK that making the Brexit link should “hang their heads in shame”.