The former Commons Speaker John Bercow has described parliamentary staff members who allege that he bullied people as “snobs and bigots”, and claimed he is the victim of a concerted campaign to destroy his reputation.

In conversation with Owen Jones at a Guardian Live event in Sloane Square in central London, he mocked those who have complained about him and denied all the allegations surrounding his behaviour.

The former Conservative MP said: “I was astonished when those allegations first surfaced on Newsnight nearly two years ago and for the best part of two years I’ve had to put up with this issue being weaponised against me.”

Robert Rogers, who was clerk of the Commons for three years during Bercow’s tenure before becoming a crossbench peer in 2014 as Lord Lisvane, has filed a formal complaint about the former Speaker to the parliamentary commissioner for standards.

Lt Gen David Leakey has also formally complained, as has his former private secretary Angus Sinclair, 67, who has passed information regarding bullying to an independent bullying and harassment helpline for current and former House of Commons staff.

Bercow told the event: “More recently it’s very obvious there is a concerted and orchestrated campaign to assassinate my character.”

He said staff members worked closely with him for a decade and he had a range of loyal employees, which he said contrasts with the narrative of what he called the “snobs and bigots faction”.

He said: “One characteristic that so far several of the detractors have in common, and they are now going public, briefing, smearing, trying to use the media to prosecute the case against me ... is that they are institutionalised. They are change-resistant and they are people who are very long accustomed not just to having their say but to having their way.”

He said they were reacting to the fact that “this bloke, to whom they regarded themselves as much superior, [who said] ‘No, its going to be done differently’ had frustrated them”.

Putting on a posh voice, he broke into a impression of one staffer, saying: “It would be inadvisable Mr Speaker ... I cannot possibly commend that motion to you.”

He said he was also patronised by some staff, adding: “I make no apology for the fact that I fought my corner. But the idea I was some sort of raging bull ... has no credibility at all.”

He said one of the complainants never worked with him closely and clashed with him in 2011 and 2013 over ceremonial visits, adding: “This is a guy who attached enormous weight to his own status.”

He said he has been “puffing himself up” and “traipsing around studios” and giving the impression he was at the heart of the Commons. “The guy is full of bigotry and prejudice.”

Bercow has not been nominated for a peerage by the Tories after he stood down in the autumn following a decade in the Speaker’s chair.

He said he “did care” that the decision had been made against him and broke precedent.

Bercow suggested that without the convention of former Speakers being sent to the Lords, future occupants of the role would be looking over their shoulders wondering if they have “hacked off the government”.