Former prime minister Sir John Major has launched an extraordinary broadside at Boris Johnson’s Government over the Owen Paterson row.

The Conservative former premier said the conduct was “shameful” and had trashed the reputation of Parliament.

And he suggested the Johnson administration was “politically corrupt” over its treatment of the House of Commons.

The Prime Minister was forced to U-turn over a plan to prevent Mr Paterson facing a 30-day Commons suspension for a serious breach of lobbying rules.

Mr Paterson subsequently quit as an MP after the Government abandoned an attempt to set up a Tory-dominated committee to re-examine his case and the wider Commons standards regime.

Sir John said: “I think the way the Government handled that was shameful, wrong and unworthy of this or indeed any government. It also had the effect of trashing the reputation of Parliament.”

The former prime minister, whose opposition to Brexit has seen him at odds with Mr Johnson’s Government, told BBC Radio 4’s Today the action of the current administration was “damaging at home and to our reputation overseas”.

Sir John, whose own government in the 1990s was undermined by sleaze rows, said: “When that happened I set up the Nolan Committee on Standards in Public Life to stop it, which has been a huge success.

“The striking difference is this: in the 1990s I set up a committee to tackle this sort of behaviour.

“Over the last few days we have seen today’s government trying to defend this sort of behaviour.

“Sleaze is unacceptable, was unacceptable when I was there, and I suffered a great deal of pain and anguish over it.

“It’s unacceptable today, and it needs to be stopped.”

He suggested there was an arrogance at the heart of Mr Johnson’s administration.

“There is a general whiff of ‘we are the masters now’ about their behaviour.”

He added: “Whenever they run up against difficulties with anybody – whether it is the Supreme Court, the Electoral Commission, the BBC, they react not with an understanding, not with trying to placate what has gone wrong, but actually in rather a hostile fashion.”

The Government has a working majority of around 80 and Sir John suggested that had allowed Mr Johnson to treat Parliament “with contempt”.

Major announcements were briefed to sections of the media before MPs, he said, and ministers had “behaved badly” in “ways that are perhaps politically corrupt”.

Mr Paterson was found to have breached lobbying rules in an “egregious” way by the Commons Standards Committee following an investigation by Parliamentary Commissioner for Standards Kathryn Stone.

But as MPs prepared to vote on a 30-day suspension, which could have triggered the recall process for a by-election, the Government threw its weight behind an amendment to appoint a new committee to look again at the case and the disciplinary system.

When that plan was ditched by the Government Mr Paterson resigned as an MP, but Downing Street has refused to rule out the possibility of recommending him for a peerage.

Sir John said that would be “rather extraordinary” and expressed doubt that it would be approved.

The debacle has led to fury among Tory MPs who were whipped to vote for the controversial plan, only to see it jettisoned.

Budget 2021
Leader of the House of Commons Jacob Rees-Mogg and Chief Whip Mark Spencer (Victoria Jones/PA)

Tory MP Andrew Bridgen said the controversial vote and subsequent U-turn had undermined confidence in the whips.

And he warned the Prime Minister that Tories could be “ruthless” if they felt their leader was losing popularity.

“Confidence in the Prime Minister within the Conservative Party will have been needlessly damaged, unfortunately,” he told the BBC’s PM programme.

He added: “The moment that a prime minister, a leader of our party, is seen as a liability and not a political asset then we tend to be fairly ruthless.”

Chief Whip Mark Spencer has been the target of largely anonymous briefings blaming him for the fiasco although Downing Street has publicly backed him.

Senior Tory backbencher Sir Geoffrey Clifton-Brown told Today that ultimately the Prime Minister was responsible for the mistakes in handling the situation.

“The Chief Whip was merely doing his job, he was collating the strands of opinion, he was then reporting that back to No 10 who decided what to do and what decisions were made,” Sir Geoffrey said.

“The Prime Minister is in charge of the party, in charge of the Government, ultimately he must take responsibility.”

Meanwhile Tammy Banks, one of the non-MPs who sits on the Standards Committee, defended the process and the work of Parliamentary Commissioner for Standards Kathryn Stone.

Business Secretary Kwasi Kwarteng had suggested her future was in doubt and allies of Mr Paterson have publicly criticised her handling of the case.

Tammy Banks, one of the non-MPs to sit on the Standards Committee, said she had been “appalled” by “slanderous” attacks on Ms Stone.

She told BBC Radio 4’s Week In Westminster: “She works hard, she does her best and above everything else she is fair.”

A Government spokesman said: “As the Prime Minister has said, paid lobbying and paid advocacy by ministers and MPs is absolutely wrong.

“All elected officials must abide by the rules of conduct, as the public have a right to expect.”