Boris Johnson could simply ignore a parliamentary vote of no confidence and proceed with a no-deal Brexit followed by an election, unless MPs can form an alternative government in 14 days, a former senior judge has said.

Jonathan Sumption, a former supreme court judge, said Johnson would be entitled to stay on as prime minister even if he lost a confidence vote.

Under the law, MPs would have two weeks to create an alternative government before an election was automatically triggered.

MPs can still thwart Boris Johnson over no deal. Here’s how | Vernon Bogdanor Read more

In those circumstances, the prime minister would have the power to set the date of the election for after 31 October, following the UK’s departure from the EU with or without a deal.

Lord Sumption told BBC Radio 4’s Today programme the prime minister “could fix the date for polling”. He said there were two main ways MPs fighting a no-deal Brexit could prevent it from happening.

The first was to “pass a statute which limited the right of the government to have a no-deal Brexit by saying they had to revoke article 50” and the second would be an interim government, he said.

Sumption argued both options seemed like “very long shots”, given the parliamentary arithmetic, but conceded the political situation was unpredictable, given the high stakes of a no-deal Brexit.

Johnson has insisted he wants a deal with Brussels but has refused to sit down for talks until the EU agreed to scrap what he called the “undemocratic backstop” – the mechanism to prevent a hard border on the island of Ireland that could keep the UK in a customs union.

Q&A Why is Boris Johnson's working majority down to one? Show Hide There are 650 MPs in total. After the Brecon and Radnorshire byelection the Conservatives have 310 MPs. They also have 10 Democratic Ulster Unionist MPs who have agreed to vote with the government on a confidence and supply basis, giving Boris Johnson a bloc of 320 MPs. In opposition, the Labour party have 245 MPs, the Scottish National party have 35, the Liberal Democrats 13, Plaid Cymru four and the Green party one. This adds up to a bloc of 298. There are 11 MPs who do not vote: the Speaker and his three deputies, and the seven Sinn Féin MPs who do not attend the Commons as a matter of principle.

There are 21 MPs who are either independent, or part of the Independent Group for Change. If all of these MPs vote against the government, along with the opposition parties, this totals 319, giving the prime minister a working majority of one.

In practice, one of those independents, Charlie Elphicke, who is currently suspended from the Tory party while charged with sexual assault, is likely to vote with the government. A further complication is that the Labour MP Jared O’Mara has been largely absent from parliament and says he intends to quit in September.

Dominic Cummings, Johnson’s senior adviser and architect of the leave vote, has made clear he would do “whatever necessary” to take the UK out of the EU by 31 October and EU officials are said to be under the impression that Brexit without a deal is the most likely scenario.

There are signs Johnson is preparing for being forced into an election by parliament, even though he insists it is the “last thing” he wants.

Speculation intensified after it emerged he has brought in Isaac Levido, the righthand man of the Australian election guru Lynton Crosby, to a new campaigning role at Conservative party headquarters.

Quick guide Who's who - Boris Johnson's controversial backroom team Show Hide Boris Johnson's new backroom team in Downing Street is littered with ex-staff from Vote Leave, supports of controversial lobbying groups like the TaxPayers’ Alliance, and those with links to Lynton Crosby and Mark Textor's C|T Group Dominic Cummings Special advisor to the prime minister Boris Johnson and chief of staff in all but name, Cummings was campaign director of Vote Leave. He had previously campaigned against Britain joining the Euro, and worked for Iain Duncan Smith as director of strategy at the Conservatives, and for Michael Gove as a special advisor in the department of education. Isaac Levido A Lynton Crosby protege, Australian Levido has been hired into Conservative party headquarters as director of politics and campaigning. He has previously worked in Washington for the Republicans, and contributed to the Tory campaigns in 2015 and 2017. Earlier this year he worked on the Liberal party’s surprise election success in Australia, where the party’s Facebook videos were watched at triple the rate of the Labor opposition videos during the election campaign. Lee Cain Head of communications for Johnson and responsible for determining the Conservative government’s message in public. He was the head of broadcast for the Vote Leave campaign and had government jobs, including at No 10, before joining Johnson at the Foreign Office. His most public role, though, was dressing up as a chicken in 2010 to heckle Tory politicians. Rob Oxley Press secretary at Downing Street, Oxley has previously served as an advisor to Home Secretary Priti Patel, and worked alongside Cain as press officer for the Vote Leave campaign. Oliver Lewis Now the Johnson government’s Brexit policy adviser, Lewis was Research Director at Vote Leave. Munira Mirza Heading up Johnson's policy unit, Mirza was his deputy mayor for arts in London for eight years. She has links to a circle of former Revolutionary Communist Party supporters who wrote for Living Marxism, before morphing into libertarian provocateurs involved with Spiked online magazine. She co-founded of the Manifesto Club, a pressure group challenging the “erosion of public freedoms”. Chloe Westley A digital adviser to the administration, Westley worked at both Vote Leave and the TaxPayers’ Alliance. She found fame on Twitter as @LowTaxChloe making videos attempting to mock attempting to mock Corbynite socialism. She was involved in Turning Point, a student pressure group dedicated to “free markets, limited government and personal responsibility” which drew attention when at one of its launch events American conservative Candace Owens appeared to praise HItler’s approach to making Germany great. Westley herself has praised the work of far-right, anti-Islam politician Anne Marie Waters. Ross Kempsell Former Guido Fawkes chief reporter and Talkradio political editor Kempsell has joined Johnson’s team as a special adviser focused on reform of Whitehall and the public sector just weeks after his interview with the prime minister during his leadership campaign prompted Johnson to rattle off an anecdote about making and painting cardboard buses as a hobby. He also was the interviewer when Johnson promised Brexit would be carried out “do or die” by 31 October. Danny Kruger Has moved from being the Department for Digital, Culture, Media and Sport’s expert adviser on charities to the role of political secretary. He stood down as a Tory candidate in 2005 after causing controversy by saying he thought there should be a “period of creative destruction in the public services”. He argues that cannabis should be decriminalised. Blair Gibbs Previously a senior adviser to both Boris Johnson and Michael Gove, Gibbs is another former TaxPayers’ Alliance staffer entering No 10 as a policy expert. He is also in favour of decriminalisation, joining the administration from a policy role at the Centre for Medicinal Cannabis.

Rebel Tory MPs are in talks with senior Labour figures about whether a government of national unity can be formed to stop Johnson pursuing no deal.

It could potentially be led by a centre-right, pro-EU Tory such as Ken Clarke or David Lidington, with the sole aim of requesting an extension to article 50, but the consequences after that are unclear.

Their preferred method is to use legislation to prevent a no-deal Brexit, rather than trying to collapse the government, but No 10 will do everything possible to deny them the opportunity for that.

Vernon Bogdanor, the constitutional expert at King’s College London, warned it would be a “Herculean task” for backbenchers to stop a no-deal Brexit at this stage but listed four possible legislative ways plus the option of bringing down the government.