It "would be a scandal that Parliament would struggle to live down" if ex-Commons Speaker John Bercow got a peerage, an ex-Parliament official has said.
David Leakey who served in Parliament as Black Rod accused Mr Bercow of "intolerable behaviour".
But Mr Bercow dismissed his claims as "total and utter rubbish".
Meanwhile Diane Abbott has been criticised for saying it was "unlikely" ex-soldier Mr Leakey was bullied.
The shadow home secretary tweeted that Mr Leakey had "served in Germany, Northern Ireland and Bosnia. But claims he was bullied (i.e. intimidated and coerced) by John Bercow. Unlikely."
She has since deleted her tweet.
Responding to her comment, David Penman - general secretary of the FDA Union which represents civil servant - said: "What a ridiculous comment from an experienced MP, demonstrating blind political partisanship and a complete failure to understand how power is abused in the workplace."
And Labour MP Dan Jarvis - who served as an army officer - said "having a distinguished service record does not preclude you from being a victim of workplace bullying".
"All of us in the Labour/trade union movement have a responsibility to create a climate where people can voice their concerns and not have their experiences dismissed out of hand."
Mr Bercow has confirmed that he had been proposed for a peerage by outgoing Labour leader Jeremy Corbyn.
Getting a peerage would enable Mr Bercow to sit in the House of Lords - but he has suggested Downing Street is seeking to block his appointment to the upper chamber.
Speaking to the BBC's Today programme, Mr Leakey argued Mr Bercow should not be given a peerage on the grounds of his behaviour as Speaker.
"He would fly into a rage, the red mist would descend, and he would be jumping up and down and balling out, and shouting insults," he said.
"He called me an anti-Semite once after being rather rude and insulting about my background, education and military career."
In 2018 Mr Leakey accused the ex-Speaker of creating a climate of "fear and intimidation" and more recently has said he would submit a dossier to the Parliamentary Commissioner for Standards detailing his complaints.
Lord Lisvane, who served as Clerk of the House between 2011 and 2014, has confirmed to the BBC he has submitted a formal complaint, which was understood to be centred around bullying.
Hitting back at the accusations, Mr Bercow told Sky News the claims were "total and utter rubbish".
He said Mr Leakey was "not employed by me, he wasn't an employee of the House of Commons".
"He is in absolutely no position whatsoever to comment on my relations with my parliamentary colleagues, of which he is completely and utterly ignorant.
"What we have got here is somebody who left the House, who is thrashing about, desperate to remain relevant, popping up at every turn, trying to make himself seem very important, very centre-stage, very at the heart of things in the way that I went about my work."
In response, Mr Leakey said Mr Bercow "either doesn't understand or can't remember how the role of Black Rod operates" adding that "30% of my work was within or for the House of Commons".
Mr Bercow stepped down as Speaker in October after 10 years in the role and was replaced by Sir Lindsay Hoyle.