John Bercow has insisted it is "so blindingly obvious" that Tory front-runners will not be able to suspend parliament to force through a no deal.
The Speaker weighed into the row over Dominic Raab's suggestion that parliament could be prorogued to ensure Brexit happens on 31 October, saying MPs "will not be evacuated" from the decision-making process.
It comes as Tory leadership rivals tore into each other, with ex-minister Sam Gyimah accusing his rivals of "Trumpian machismo".
Meanwhile, voters have been heading to the polls in Peterborough to replace disgraced MP Fiona Onasanya, with Nigel Farage's Brexit Party hoping to snatch the seat from Labour.
To follow events as they unfolded, see our live coverage below
Theresa May has travelled to France today for the 75th anniversary commemorations of D-Day. Alongside Donald Trump and other world leaders, she paid tribute to those who served during the landings.
"If one day can be said to have determined the fate of generations to come, in France, in Britain, in Europe and in the world, that day was the 6 June 1944," she said.
"More than 156,000 men landed on D-Day, of which 83,000 were from Britain and the Commonwealth.
"Over a quarter of a million more supported operations from air and sea, while the French Resistance carried out extraordinary acts of bravery from behind enemy lines.
"Many were terribly wounded, and many made the ultimate sacrifice that day, and in the fierce sacrifice that followed, as together our Allied nations sought to release Europe from the grip of fascism."
The prime minister read the names of several British troops who were killed during the D-Day landings and the Battle of Normandy.
"These young men belonged to a very special generation, the greatest generation," she said.
"A generation whose incomparable spirit shaped our postwar world.
"They didn't boast. They didn't fuss. They served."
On the 75th anniversary of D-Day, more than 120 military veterans have signed a letter warning that peace and friendship in Europe is threatened by Brexit.
The 122 veterans, whose service spans the period from the Second World War to modern-day conflicts in Iraq and Afghanistan, said that the peace which has prevailed in Europe since 1945 “should not be taken for granted”.
The letter came as D-Day veteran Eric Chardin, who was 19 when he took part in the 1944 landings, said that the prospect of Brexit worried him.
More here from our political editor Andrew Woodcock:
Back in Westminster, the Tory leadership race has turned ugly after Brexiteer frontrunner Dominic Raab made the extraordinary suggestion that parliament could be prorogued to force through a no-deal Brexit.
Prorogation is the term for the end of a parliamentary session, the formal period before there is a new Queen' Speech with the government's plans for new laws.
Parliament can be prorogued ahead of schedule to prepare for a general election, such as before the snap election in 2017.
But Raab's suggestion is pretty extreme as he would dissolve parliament to prevent it from blocking a no-deal Brexit on 31 October - effectively overruling the will of MPs, and therefore the public.
He made the claims at an action-packed leadership hustings, which my colleague Ben Kentish covered last night.
Read his piece here:
Conservative leadership candidate Sam Gyimah has accused male rivals of "Trumpian machismo" for claiming they can negotiate a better Brexit deal with Brussels than Theresa May.
As the Tory leadership race became increasingly bitter, the former minister, who is standing on a second referendum ticket, added those wanting to pursue a no-deal exit must gain public consent.
His remarks came as Dominic Raab, the ex-Brexit secretary, prompted outrage by suggesting he could temporarily suspend parliament in order to force through a no-deal Brexit if he succeeded Ms May.
More here:
There were several interesting stories from last night's leadership hustings, organised by the One Nation group of Tory moderates.
Matt Hancock, the health secretary, caused a stir by calling Jeremy Corbyn “an antisemite”.
On the 75th anniversary of D-Day, Mr Hancock told Tory MPs they must deliver Brexit or else “end up with the first antisemitic leader of a western nation since the Second World War”.
Senior Tories have often criticised Mr Corbyn over his handling of antisemitism but Mr Hancock’s comments are the first time that a sitting cabinet minister has directly accused the Labour leader of being antisemitic.
In response, a Labour spokesperson said: “This baseless political attack rings hollow from a minister in a party that has supported governments that actively promote antisemitic policies in Hungary and Poland, and has spent the week wooing Trump – the man who refused to condemn neo-fascists in Charlottesville who chanted ‘Jews will not replace us’.
“Numerous candidates in the Conservative leadership contest have been accused of racism, Islamophobia, homophobia and misogyny, one of whom may be the next prime minister.”
International development secretary Rory Stewart was scathing about Mr Raab's assertion that he would be prepared to temporarily shut down parliament to ensure Brexit occurs on 31 October.
Mr Stewart told ITV's Peston: "All this talk about no-deal Brexit is a recipe for delay. It can't be done.
"And the the reason why Dom Raab is saying he is going to prorogue Parliament, in other words try to shut the doors on Parliament, is because the only way that they could try to get it through is by doing that.
"That would be illegal, if they did it for the express purpose of getting it through.
"It would be unconstitutional. It would be undemocratic. And it wouldn't work."
The constituency, which voted Leave by 60.9 per cent, is traditionally a closely fought battle between Labour and the Conservatives.
Labour won the seat in 2017 with a wafer-thin majority of 607.
Fifteen candidates are standing in Thursday's by-election, which was called after disgraced MP Fiona Onasanya was forced out for lying over a speeding offence.
Both Labour and the Conservatives have campaigned hard ahead of the June 6 by-election, with Labour leader Jeremy Corbyn, former prime minister Gordon Brown and Tory big guns Boris Johnson and Jeremy Hunt all visiting the city in the lead-up.
But Nigel Farage's Brexit Party, which won 29 seats in the European elections, has also campaigned hard in its first tilt at a Westminster seat.
Labour's by-election candidate, Unite activist Lisa Forbes, faced controversy in the week before the poll over a Facebook post she "liked" which said Theresa May has a "Zionist slave masters agenda".
She told The Sunday Times she apologised "wholeheartedly for not calling out these posts" and that she had liked the video attached to the post, "not the views expressed in the accompanying text".
Liam Fox has faced several questions over whether the NHS will be on the table in a US-UK trade deal after Brexit. This was a major row when Donald Trump was in town (see here).
Dr Fox, the international trade secretary, insisted the NHS was "not and will not be for sale" when pressed on the issue by Labour's Stephen Hepburn and Tory MP Tom Pursglove.
Labour's Rupa Huq goes further, asking him to commit to never making it a part of any deal. He refers her to his earlier answer.
Tory leadership hopeful Rory Stewart makes his debut, saying the world faces a "climate cataclysm" and says he would like to double the money the Department for International Development spends on climate and the environment.
Labour's Dan Carden praises him for standing out among Tory leadership candidates amid "populists, potty mouths and parliamentary proroguers".
Stewart jokes his endorsement is the 'nail in the coffin' of his leadership bid.
Nigel Farage, the Brexit Party leader, is joining campaigners in Peterborough today as the party makes its final drive for a sensational by-election breakthrough which could deliver its first MP.
Sources close to Mr Farage were seeking to play down expectations of a runaway victory, describing bookmakers’ odds as tight as 1/7 on the Brexit Party as “nuts”.
But figures showing the Eurosceptic party scooped 16,196 votes in the city in the European elections – more than twice the tally of runners-up Labour – have fuelled anticipation of a dramatic upset in a seat that has for decades been a fiercely-contested Labour/Conservative marginal.
Read our preview here:
Labour will be unable to win a majority in a general election unless it changes its stance on a second referendum, new analysis of polling suggests.
Jeremy Corbyn’s party stands to lose more than 40 per cent of voters who backed Labour in 2017, with support overwhelmingly switching to Remain-backing parties.
The figures come as one of Labour’s shadow Brexit ministers, Jenny Chapman, swung behind a Final Say referendum, having previously been a staunch opponent.
MPs could lose the chance to hold a confidence vote in a new Tory prime minister, as a new PM might not be in place by summer recess.
Acting Commons leader Mel Stride was asked if a new prime minister would be in place to face parliament before the break by Tory MP Peter Bone.
He replied: "The answer to that question is an interplay between when the contest in the Conservative party for the new leader is due to conclude and of course when the recess itself is announced.
"And as we don’t know the answer to the latter, and I’m not sure that we entirely know the answer to the former, I think the answer unfortunately is, no, not necessarily."
MPs could be sent home for their summer break before they have been given the chance to approve the new prime minister, a cabinet minister has suggested.
Mel Stride, the leader of the House of Commons, told MPs he could not rule out the summer recess beginning before the end of the Tory leadership contest, meaning the new prime minister would have almost two months in office before having to face a confidence vote.
Labour has said it will force such a vote as soon as the new leader is in place, but the summer recess could deny them the chance to do so until September.
The PM will continue "trying to deliver for the people of this country", Downing Street said on Theresa May's last full day as Conservative Party leader.
Ms May will continue as Prime Minister until a new Tory leader is elected, at which point she will tell the Queen she is stepping aside for a successor who can command the confidence of the House of Commons.
Under the timetable set out by the Tory Party, Mrs May will formally resign as leader on Friday, with her successor elected in the week beginning July 22.
The prime minister's official spokesman said: "You have heard the PM talk passionately about some of the domestic policy issues which she cares about.
"She will continue to focus on trying to deliver for the people of this country.
"In relation to Brexit, the PM said it wouldn't be for her to take this process forward, that will be for her successor."
The backlash has already begun on the idea that the new PM would not be face the Commons until after recess.
Addressing acting Commons leader Mel Stride, Labour former minister Chris Bryant said: "I think your answers on prorogation and on whether a new PM will address the House swiftly after being elected have been wholly inadequate so far.
"It must surely be on a Venezuelan scale of outrage if we were to prorogue parliament simply so as to force through a no-deal Brexit against the will of parliament."
