Boris Johnson’s wafer-thin majority vanished before his eyes in the House of Commons this afternoon, as Philip Lee MP crossed the floor to join the Liberal Democrats.

Lee said in a statement: “This Conservative Government is aggressively pursuing a damaging Brexit in unprincipled ways. It is putting lives and livelihoods at risk unnecessarily and is wantonly endangering the integrity of the United Kingdom.”

Lee had been touted as one among the growing list of Tory rebels expected to vote against the government tonight. If anti-no deal MPs managed to take control of parliament’s agenda this evening in a bid to stop a no deal Brexit, the chances of an early general election were evermore likely. However, now that Johnson has lost his official majority the likelihood of an imminent election is becoming increasingly certain.

MPs returned to parliament this afternoon for the first time since summer recess – just a week after Boris Johnson announced his plans to prorogue parliament, limiting the scope for anti-no deal MPs to legislate against a no deal Brexit. His plans have forced MPs to act quicker than anticipated – and all should come to a head this evening.

A coalition of anti-no deal MPs, including all opposition parties and a growing cabal of Tory rebels, will try to take over the business of the House of Commons via an emergency debate to pass legislation calling on Johnson to seek a further Brexit extension. If he is unable to strike a new deal with the EU, and pass it through the Commons, by 19th October the bill would require him to seek an extension to 31st January 2020. Alternatively – if Johnson can find a majority for no deal before then he could proceed with that, which is not-so-secretly understood to be the government’s preferred option.

The usual health warnings apply, however. Any requested extension to Artice 50 must be approved by all members of the European Council. Macron was hard to win over the last time (when Theresa May requested a third extension), and there are no guarantees that he, or another council member wouldn’t veto the request and kick the UK out anyway.

But it will likely never come to that. Boris Johnson ran his leadership campaign on a pledge of taking the UK out of the EU by 31st October – “come what may,” “do or die.” He indicated last night in a statement outside No 10 Downing Street that if MPs tried to block no deal he would seek a general election. An anti-no deal bill “would create paralysing uncertainty”, as Foreign Secretary Dominic Raab told BBC Radio 4 this morning – not only is it clearly designed to delay Brexit, but probably cancel it in its entirety, he added. The best course of action, then, is taking the question back to the people in the form of a general election.

But of course there are more complications to come – this is Brexit, after all. For Johnson to call an early election he has to, under the conditions of the Fix Term Parliament Act, obtain the backing of 2/3s of the House – that means Labour will have to be onside. In normal times that shouldn’t be a problem. What opposition party would say no to a general election and a chance at power? But these aren’t exactly normal times, and despite Corbyn angling for a general election for nearly two years now there are whisperings that Labour is divided on whether to back Johnson’s call for one.

Corbyn has said he would be delighted to “take fight to the Tories,” while shadow Northern Ireland secretary Tony Lloyd said Labour would “not fall for Boris Johnson’s trick” by agreeing to a general election. The government has indicated the election would be held on 14th October, a few days before the crucial European summit. But – opposition parties do not trust Johnson not to amend the date of the election after it’s approved by parliament, pushing to to after 31st October, allowing the UK to crash out with no deal anyway.

Leader of the SNP in Westminster, Ian Blackford, wants a general election too, but emphasised that opposition MPs “need to be able to influence the date of that election.”

“We know exactly what Boris is up to” he added.

That could leave Johnson in a serious bind – having his route to no deal Brexit 31st October blocked by legislation, and not having the necessary support for a general election. There is an alternative suggestion floating around. The government could sidestep the now much-maligned Fix Term Parliament Act and table a motion for an election anyway. In that case he would require only the backing of half of MPs. But the catch – there’s always one – is that any motion like that could be amended by anti-no deal MPs to rule out no deal, or to bind Johnson’s hands on the date of the election.

So the government could be trapped. The so-called “aggressive operation” currently underway against potential Tory rebels was probably designed to avoid this outcome: reports emerged from No 10 that the government would deselect any Tories who rebelled against the government in the vote tonight, hoping it would deter their efforts to sully the governments move towards no deal.

However, in an astonishing interview this morning Philip Hammond seemed to indicate that this threat has only strengthened the Tory rebels’ resolve. He criticised the “rank hypocrisy” of Johnson’s administration for threatening to expel rebels considering Boris himself voted against May’s Brexit proposals. And, he added that he believed there were enough Tory MPs prepared to rebel for the motion to pass.

Rory Stewart, Philip Hammond, Dominic Grieve, Justine Greening and David Gauke are some of the bigger names among those who have confirmed they would defy the government this evening. Other possible rebels may include Guto Bebb, Ed Vaizey, Antoinette Sandbach and Kit Harrington. Eyes will be on David Lidington – May’s de facto deputy – who’s a known party loyalist, but also an anti-no deal advocate. If he rebels the depth of the rift in the party will be exposed as greater than possibly anticipated.

Behind all of this is Boris Johnson’s chief advisor Dominic Cummings. Cummings may have landed Johnson in a serious bind. But, Cummings is a serious strategical force – and if Boris Johnson was serious about his pledge to take the UK out of the EU “come what may” we shouldn’t underestimate the lengths the pair might go to.