The Tories’ refusal to nominate scandal-hit former Commons Speaker John Bercow for a peerage “could be a form of bullying”, a senior Labour MP has said. 

Shadow equalities minister Dawn Butler said the Bercow should be given “due process” and suggested Boris Johnson’s party only declined to nominate him for a peerage because of his stance on Brexit. 

Bercow has himself been accused by three senior ex-Commons staff of bullying during his time as Speaker.

In an attempt to uphold the convention of former Speakers getting seats in the Lords, Labour leader Jeremy Corbyn has nominated Bercow for a peerage.

But the decision is mired in controversy, with the Sunday Times reporting that his former private secretary Angus Sinclair has now joined former Commons clerk Lord Lisvane and Lieutenant-General David Leakey, previously Black Rod, in raising bullying complaints.

Tory cabinet minister Robert Jenrick insisted on Sunday that “parliament is a better place without John Bercow in it”.

Butler sought to defend Bercow, telling Ridge on Sunday on Sky News: “It is the norm that the Speaker of the House is always given a peerage so I think the first question for me is why hasn’t he been given a peerage from the Conservatives?”

She added: “I would like to know the reason why he wasn’t given a peerage. I suspect it’s actually do to with Brexit rather than anything else.

“The other thing is due process has to happen so if you accuse somebody of bullying there has to be due process.”

She went added: “We really do need to ask the Conservatives why is it that you haven’t like everybody else ensured that the Speaker of the House is given a peerage? Otherwise I think that is a form of bullying too.”

Jenrick said he did not agree with Butler and that there was “no obligation” on Boris Johnson to make Bercow a peer. 

“Personally I wouldn’t offer John Bercow a peerage,” he the Communities Secretary said.

“I think you have seen some very serious allegations of bullying and harassment from senior credible people including a Lt Gen who worked with him.

“These are important things that need to be investigated before any decision like that is taken.

“And in my own experience parliament is a better place without John Bercow in it, long may that continue.”

He added: “John Bercow never believed in convention himself when he was Speaker, he explicitly said that he didn’t think the conventions needed to be abided by.

“He said if you do that nothing ever changes.”

Leakey said this week it would be a  “scandal” if Bercow was given a peerage.

The former Black Rod, who in charge of the day to day running of the House of Lords, told the BBC that there were times Bercow “would fly into a rage” and “the red mist would descend”.

Shadow home secretary Diane Abbott sparked fierce criticism earlier this week when she dismissed the idea that Leakey, a former soldier, could be bullied.

The House of Commons meanwhile said it was “unacceptable” for Bercow to publicly name parliamentary staff in his autobiography, which was released this week, without their permission. 

Bercow has also been accused of bullying by Lord Lisvane, who was clerk of the House.

The former Speaker told Sky News earlier this week that the allegations against him were “total and utter rubbish – from start to finish”.

In a separate statement, Bercow said the allegations against him came at a “curious” time as he seeks to become a peer.

He also attacked the government for not elevating him to the Lords after his retirement as Speaker. 

Bercow left the Speaker’s chair on October 31 and has been replaced by Lindsay Hoyle.