Boris Johnson will attempt to reform the House of Commons standards watchdog following its decision to ban Owen Paterson, the former Cabinet minister, from Parliament.

Tory MPs and ministers will be ordered by the Government’s whips to support a backbench motion which could lead to the Commons standards committee system being disbanded and replaced with a new body.

Ministers believe this unprecedented move could lead to the resignation of Kathryn Stone, the Commons standards commissioner, who has been accused of bias against Tories and Brexiteers.

John Whittingdale, the former Conservative Culture secretary, has been lined up to chair a new nine-strong select committee, with most of the members nominated by the Government, which is likely to redraw the rules on MPs’ conduct.

MPs had been expected to vote on a proposal that Mr Paterson be banned from the Commons for 30 days for alleged breaches of lobbying rules, which could have led to him facing a by-election.

However, an amendment to the motion tabled on Tuesday night by Dame Andrea Leadsom, a former leader of the House of Commons, is likely to lead to the break-up of the current standards watchdog system if it is passed.

The motion, which will be formally published on Wednesday morning, must be selected by Sir Lindsay Hoyle, the Commons speaker, after Prime Minister’s Questions for debate.

One senior Cabinet source said that the proposed punishment for Mr Paterson – whose wife Rose took her own life last year, mid-way through the investigation – was “the straw that broke the camel’s back”.

Leadsom amendment

The Leadsom amendment recommends that “the current standards system should give Members of Parliament the same or similar rights as apply to those subject to investigations of alleged misconduct in other workplaces and professions”.

That would include the “right of representation, examination of witness and appeal”, it said.

It proposes that the new Whittingdale committee will comprise four Tory MPs, three Labour MPs and one SNP MP. 

Nominations for the new posts must be made by November 15. The committee will be allowed to appoint legal advisers to assist with its review. Its findings will be reported by February 3.

The Leadsom amendment is supported by senior Tories including Sir Bernard Jenkin, a member of the Standards committee who recused himself over the Paterson report because of his friendship with him, and Sir Iain Duncan Smith, the former party leader.

Writing in the House magazine, Sir Bernard – who is also chairman of the House of Commons liaison committee – said that Ms Stone’s role in future “should be divided”.

He said: “The commissioner should investigate but not adjudicate. Adjudication should be independent and separate.

“And there should be a further person or body which promotes the positive learning and professional development of members in matters of ethics and standards, as in other professions.

“The Committee on Standards should have proper powers – and the time – to oversee the operation of the system but should no longer decide on individual cases.

“MPs adjudicating on the conduct of their own colleagues, whom they know, can never command public confidence. It would never be allowed in the General Medical Council or the Bar Council.”

Pressure on standards commissioner

Ms Stone has been a repeated thorn in the side for top Tories and launched an inquiry into the funding of Boris Johnson’s luxury holiday in Mustique.