MPs have defeated the Government in a crucial House of Commons vote to stop the new prime minister suspending parliament to force a no-deal Brexit through.
The House of Commons voted by 315 to 274 to back an amendment to Northern Ireland legislation which will force the government to hold debates in parliament in the run-up to the Brexit date of 31 October.
Culture minister Margot James quit the Government in order to join 17 Tory rebels, while four Cabinet ministers - including chancellor Philip Hammond - abstained.
Downing Street said Theresa May was "disappointed" at the abstentions, but the four ministers were not sacked.
And Tory leadership contender Jeremy Hunt was forced to admit he had abstained by accident, as he wrongly believed he had been given permission to miss the vote.
The likely winner of the Tory leadership contest, Boris Johnson has not ruled out asking the Queen to use a mechanism called prorogation to lock the doors of the Commons on MPs who might otherwise block a no-deal Brexit.
But the amendment to the Northern Ireland (Executive Formation) Bill will require the government to publish fortnightly reports this autumn on the state of talks on the restoration of power-sharing institutions, and to table a motion for MPs to vote on.
Crucially, this motion will be amendable, allowing MPs to add clauses to rule out no-deal.
If the Commons is prorogued at the time, the amendment, tabled by Labour MP Hilary Benn, states that it must be recalled to sit for at least five days.
Cabinet ministers Philip Hammond, David Gauke, Rory Stewart and Greg Clark - all declared opponents of a no-deal Brexit - all abstained. Northern Ireland secretary Karen Bradley had permission not to take part in the vote.
Mr Hammond said: "The Conservative Party has always, at its core, had a fundamental belief in the importance of strong institutions – and in a representative democracy there can be no more vital institution than its Parliament.
"It should not be controversial to believe that Parliament be allowed to sit, and have a say, during a key period in our country’s history."
Mr Hunt said he failed to vote by accident, having wrongly thought he had been "slipped" - given permission to stay away.
"I missed votes today because I thought I was slipped and it turns out I was not," said the foreign secretary. "Apologies to my colleagues and whips' office. My position is that parliament should not restrict the hands of an incoming government in this way and I remain opposed to how parliament voted."
Also backing the amendment were former ministers Guto Bebb, Steve Brine, Alistair Burt, Jonathan Djanogly, Justine Greening, Dominic Grieve, Sam Gyimah, Richard Harrington, Philip Lee, Sir Oliver Letwin, Sarah Newton and Ed Vaizey as well as fellow Tory MPs Jeremy Lefroy, Paul Masterson, Antoinette Sandbach and Keith Simpson.
A Downing Street spokesman said: “The Prime Minister is obviously disappointed that a number of ministers failed to vote in this afternoon’s division. No doubt her successor will take this into account when forming their government.”
Shadow Brexit secretary Sir Keir Starmer welcomed the result, saying: "For Boris Johnson to try to shut down parliament to force through a destructive no-deal Brexit would be a constitutional outrage. Now it would also be unlawful. A huge victory."
Mr Djanogly said that suspension of parliament to force no-deal through would have led to "civil insurrection and violence".
"Prorogation for Brexit purposes would have been damaging to our constitution and the Conservative Party and have led to civil insurrection and violence," tweeted the new justice minister. - Parliament's dismissal of this absurdity will be appreciated by our new PM - whether they admit to it or not."
Liberal Democrat leadership hopeful Sir Ed Davey said the result amounted to "the first defeat of Johnson before he's even taken office".
"The outrageous failure of him to rule out proroguing parliament has been an utter disgrace. Parliament has just stood up against tyranny," said Davey.
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