Boris Johnson has been accused of behaving like a Stuart monarch who believes he has the "divine right to rule", after Downing Street said the UK would leave the EU on 31 October "whatever the circumstances".

Boris Johnson’s official spokesman repeatedly declined to say whether the prime minister would respect a Commons vote to prevent no-deal, insisting that it was a “hypothetical” issue as no such motion has yet been tabled.

His comments came after Mr Johnson’s senior adviser Dominic Cummings reportedly said that a vote of no confidence in the PM could not stop no-deal, as he could simply call a general election for a date after the Brexit deadline of 31 October, ensuring EU withdrawal happened during the campaign.

But the prominent Tory opponent of no-deal, Dominic Grieve, dismissed Mr Cummings' suggestion as "complete and total nonsense", insisting that it would be open to MPs following a no-confidence vote to install a new administration willing to delay Brexit to avoid crashing out without an agreement.

"The suggestion that Mr Johnson can stay in office after a vote of no confidence if an alternative administration is capable of taking office is complete and total nonsense," Mr Grieve told The Independent.

And Labour MP Stephen Doughty, a leading supporter of the People's Vote campaign for a second referendum, said: “The PM’s spokesperson needs to catch up with the news. It is more than 320 years since the question of whether parliament or the executive is sovereign was settled, and parliament won.

"Instead of impersonating Stuart monarchs and claiming a divine right to rule, the prime minister and his retinue should recognise they have to submit to democracy and have no right to impose no-deal or any vicious Brexit on us. Instead, it is time to trust the people and let us be heard in a Final Say referendum on whatever comes out of the Brexit crisis."

Asked at a regular Westminster media briefing whether the PM agreed it was now too late for MPs to stop no-deal, Mr Johnson’s spokesman said: “The UK will be leaving the EU on 31 October, whatever the circumstances. There are no ifs or buts.

"We must restore trust in our democracy and fulfil the repeated promises of parliament to the people by coming out of the EU on 31 October.

"Politicians cannot choose which votes to respect. They promised to respect the referendum result and we must do."

Boris Johnson's cabinet: Who's in and who's out Show all 40 1 /40 Boris Johnson's cabinet: Who's in and who's out Boris Johnson's cabinet: Who's in and who's out In: Jacob Rees-Mogg Jacob Rees Mogg appointed Leader of the Commons AFP/Getty Boris Johnson's cabinet: Who's in and who's out In: Esther McVey Esther McVey appointed housing secretary AFP/Getty Boris Johnson's cabinet: Who's in and who's out In: Jo Johnson Jo Johnson appointed new business and energy secretary EPA Boris Johnson's cabinet: Who's in and who's out In: Brandon Lewis Brandon Lewis appointed immigration secretary Getty Boris Johnson's cabinet: Who's in and who's out In: James Cleverly James Cleverly appointed Conservative Party chairman PA Boris Johnson's cabinet: Who's in and who's out In: Baroness Evans Baroness Evans remains Leader of Lords PA Boris Johnson's cabinet: Who's in and who's out In: Julian Smith Julian Smith appointed Northern Irish secretary Reuters Boris Johnson's cabinet: Who's in and who's out In: Alister Jack Alister jack appointed Scottish secretary PA Boris Johnson's cabinet: Who's in and who's out In: Alun Cairns Alun Cairns remains Welsh secretary AFP/Getty Boris Johnson's cabinet: Who's in and who's out In: Grant Shapps Grant Shapps appointed transport secretary Getty Boris Johnson's cabinet: Who's in and who's out In: Alok Sharma Alok Sharma appointed international development secretary AFP/Getty Boris Johnson's cabinet: Who's in and who's out In: Robert Buckland Robert Buckland appointed justice secretary Getty Boris Johnson's cabinet: Who's in and who's out In: Amber Rudd Amber Rudd remains work and pensions secretary Getty Boris Johnson's cabinet: Who's in and who's out In: Robert Jenrick Robert Jenrick appointed housing and communities secretary AFP/Getty Boris Johnson's cabinet: Who's in and who's out In: Andrea Leadsom Andrea Leadsom appointed business secretary Reuters Boris Johnson's cabinet: Who's in and who's out In: Nicky Morgan Nicky Morgan appointed culture secretary Getty Boris Johnson's cabinet: Who's in and who's out In: Gavin Williamson Gavin Williamson appointed education secretary AFP/Getty Boris Johnson's cabinet: Who's in and who's out In: Theresa Villiers Theresa Villiers appointed environment secretary AFP/Getty Boris Johnson's cabinet: Who's in and who's out In: Liz Truss Liz Truss is appointed international trade secretary Reuters Boris Johnson's cabinet: Who's in and who's out In: Ben Wallace Ben Wallace appointed defence secretary EPA Boris Johnson's cabinet: Who's in and who's out In: Stephen Barclay Stephen Barclay remains EU secretary AFP/Getty Boris Johnson's cabinet: Who's in and who's out In: Dominic Raab Dominic Raab appointed foreign secretary AFP/Getty Boris Johnson's cabinet: Who's in and who's out In: Priti Patel Priti Patel appointed home secretary AFP/Getty Boris Johnson's cabinet: Who's in and who's out In: Michael Gove Michael Gove given Chandellor of the Duchy of Lancaster AFP Boris Johnson's cabinet: Who's in and who's out In: Sajid Javid Sajid Javid is appointed Chancellor of the Exchequer AP Boris Johnson's cabinet: Who's in and who's out Out: Jeremy Hunt Jeremy Hunt sacked as foreign secretary Reuters Boris Johnson's cabinet: Who's in and who's out In: Matt Hancock Matt Hancock remains health secretary AFP/Getty Boris Johnson's cabinet: Who's in and who's out Out: Chris Grayling Chris Grayling resigned as transport secretary Getty Boris Johnson's cabinet: Who's in and who's out Out: Jeremy Wright Jeremy Wright sacked as culture secretary PA Boris Johnson's cabinet: Who's in and who's out Out: Karen Bradley Karen Bradley sacked as Northern Ireland secretary Getty Boris Johnson's cabinet: Who's in and who's out Out: James Brokenshire James Brokenshire sacked as housing and communities secretary Reuters Boris Johnson's cabinet: Who's in and who's out Out: Penny Mordaunt Penny Mourdaunt sacked as defence secretary Reuters Boris Johnson's cabinet: Who's in and who's out Out: Liam Fox Liam Fox sacked as international trade secretary Getty Boris Johnson's cabinet: Who's in and who's out Out: Greg Clarke Greg Clarke sacked as business secretary PA Boris Johnson's cabinet: Who's in and who's out Out: David Mundell David Mundell sacked as Scottish secretary Getty Boris Johnson's cabinet: Who's in and who's out Out: Damien Hinds Damien Hinds sacked as education secretary Getty Boris Johnson's cabinet: Who's in and who's out Out: David Gauke David Gauke resigned as justice secretary EPA Boris Johnson's cabinet: Who's in and who's out Out: Rory Stewart Rory Stewart resigned as international development secretary Getty Boris Johnson's cabinet: Who's in and who's out Out: David Lidlington David Lidlington resigned as deputy Prime Minister PA Boris Johnson's cabinet: Who's in and who's out Out: Philip Hammond Philip Hammond resigned as Chancellor of the Exchequer AFP/Getty

Asked repeatedly whether Mr Johnson would respect the result of a vote in parliament to block no-deal or to express no confidence in him as PM, the spokesman said; “I’m not in the business of talking about things that haven’t happened.”

And when he was challenged on whether Mr Johnson would observe as a general principle the requirement to respect the result of parliamentary votes, the spokesman replied: “There aren’t votes that have taken place. I am not engaging in some hypothetical game.”

Under electoral law, after MPs pass a vote of no-confidence in the prime minister, an election is triggered if neither the existing PM or an alternative is able to win the confidence of the Commons in a vote over the following 14 days.

Although it seems unlikely that Labour leader Jeremy Corbyn would be able to win a confidence vote in that time, anti-Brexit MPs have suggested that it may be possible for a unity candidate - such as Hilary Benn or Sir Oliver Letwin - to do so on the single policy of extending Brexit negotiations to avoid no-deal.

But Mr Cummings’ reported comments suggest that he believes Mr Johnson could simply sit the 14 days out before calling a poll for November, ensuring that MPs were away from parliament at the key moment when Brexit happens.

Mr Johnson’s spokesman declined to comment on reports that cabinet secretary Sir Mark Sedwill had advised the PM that he would be bound by convention not to take major policy decisions - such as taking the UK out of the EU - during the campaign period.

Dominic Cummings outside Downing Street (AP)

Attorney general Sir Geoffrey Cox is reported to believe that there is no legal bar to EU withdrawal during an election period.

And the PM’s spokesman told reporters: “The legal default, as put in place by parliament, is that the UK will leave on 31 October with or without a deal.”

Mr Grieve insisted on Sunday that there remain “a number of things” which the House of Commons can do to prevent no-deal, including bringing down the Government and setting up a new one in its place.

But asked whether he believed parliament could stop Mr Johnson from taking the UK out of the European Union without a withdrawal agreement, health secretary Matt Hancock told BBC Radio 4’s Today: “ I now don’t think it can.

“I thought that it could and the votes went differently to what I anticipated. When the facts change, even as a politician you have to change your mind.”

Health secretary Matt Hancock (AFP/Getty)

Mr Hancock denied that the government was planning for an early election to force no-deal through.

“Honestly, I haven’t talked to Dominic or the prime minister or anybody else in Westminster about this idea,” he said.

"I don't want one. I don't think we need one.

"I think what we need is to deliver Brexit and to deliver on our top domestic priority, which is the NHS.”

During the campaign for the Tory leadership, Mr Hancock was one of the few candidates ruling out the no-deal option, which he said was “unachievable” because of the scale of opposition in the Commons.

He said that he changed his mind after a vote a few days later on 12 June, in which the Commons rejected by 309 votes to 298 a motion tabled by Labour’s Jeremy Corbyn, which would have allowed MPs to take control of the parliamentary timetable in the autumn to stop no-deal going through.

“Parliament was asked if it would stop a no-deal Brexit,” said Mr Hancock. “I thought that would go through and in fact the government won by 11. It has changed my mind because the parliamentary arithmetic didn’t play out as I expected.”

Just 10 Conservative MPs rebelled against the government in the 12 June division. Opponents of no-deal hope that their ranks would be swollen in any future vote by former ministers who followed the whip on that occasion, such as Philip Hammond, David Gauke, Rory Stewart and Greg Clark, and others who baulked at backing a motion tabled by the Labour leader.

Labour MP Anna McMorrin, a supporter of the People's Vote campaign for a second referendum, said: “Matt Hancock is simply wrong to say our sovereign parliament cannot stop a disastrous no-deal. MPs from all parties, including a number of Conservatives, have shown they are ready to seize control of the agenda or, if necessary, bring the Government down. To claim there is no majority against no-deal is patently absurd.

“Rather than downplaying the risks of no-deal, perhaps the health secretary should ask those working in the NHS what the impact would be. It is an outrage that he is willing to force this on the health service and the country without anyone except the 0.1% of the population who voted for Boris Johnson having any say over it whatsoever.