The Brexit delay is a huge moment for those wanting a Final Say referendum – here's how to avoid wasting it

MPs and the public are already shifting in favour of a new Brexit referendum. The European Council’s decision to delay our departure until the end of October gives us a fantastic opportunity to drive through to victory.

The European Parliament elections on 23 May will be a perfect platform to say why staying in the EU is in the national interest – and how giving the people the Final Say is the best way to cancel Brexit. The elections will be seen as a dry run for a referendum. If patriotic pro-Europeans turn out in force, the momentum in favour of a new vote could be unstoppable.

Nothing, of course, is in the bag. The prime minister still hopes to avoid the European elections by cutting a deal with Labour – and using its votes to get Brexit through parliament.

But why should the opposition play ball? Most Labour MPs are adamant that any Brexit deal – even a so-called softer one that involves us staying in the EU’s customs union – should be put to the people in a confirmatory ballot. If Jeremy Corbyn went against their wishes, he’d split the party and get the blame for ushering in a Tory Brexit.

Theresa May wanted to scare Corbyn with the bogeyman of European elections. But the Labour leadership seems to have clocked the fact that they could actually be in its interests. It would get 38% of the vote, while the Tories would get only 23%, according to a poll yesterday for Open Europe.

Not surprisingly, John McDonnell, the shadow chancellor, told ITV on Wednesday night that he doubted a deal would be done with the Conservatives before the European elections. With the Tories running scared, why would Labour avoid a date with the electorate?

Well, there is one reason. Unless Labour comes decisively off the fence on whether it is committed to a referendum on any Brexit outcome, many pro-Europeans (including EU citizens living here) will vote for other parties – such as the Liberal Democrats, Greens and The Independent Group. Conversely, if Corbyn stops his umming and ahhing and says clearly he wants a referendum, Labour could clean up.

Either way, pro-Europeans are likely to do well in the election. We are passionate. We have the wind in our sails. Around a million people marched for a People’s Vote last month. Over 6 million signed a petition calling for Brexit to be cancelled.

By contrast, Brexiters are down in the dogs. Many won’t turn up to vote – according to both the Open Europe poll and a similar one by YouGov. It suggested that 55% of those who backed Remain in 2016 would definitely vote in the European elections, whereas only 40% of those who voted Leave would.

Assuming pro-Europeans do well, the political landscape will look different after the elections. More MPs will back a People’s Vote if they sense public opinion has shifted. The media will give us more airtime – and the oxygen of publicity will help our cause. More Brexiters will recant – following in the footsteps of U-turns from LBC radio’s Nick Ferrari and the Daily Mail’s Peter Oborne.

MPs may also shift into our camp as the flaws of various forms of “soft” Brexit, especially a customs union, become apparent. The scheme being pushed by Ken Clarke, the Tory MP, is staggeringly vague. It is also unpopular with the vast chunk of the Conservative Party.

Fortunately, Labour is in no mood to sign up to a pig in a poke. McDonnell told ITV that if the party did manage to do a deal with the Tories, this would require legislation which has been “properly scrutinized, that is effective, that will stand the test of time”.

As a customs union is examined, it is likely to fall apart like a chocolate orange. There are a host of problems including the one that Liam Fox, the pro-Brexit trade secretary, has put his finger on – namely that the EU could sell access to our market to other countries without us having a say.

The prime minister has tried three times to get her miserable deal through parliament – and failed every time. She may have another go before the summer break. Given the Speaker’s ruling that she can’t keep putting the same vote to MPs again and again, she could try another approach, introducing legislation rather than just having a “meaningful” vote.

But May’s chances of getting MPs to back this deal are small. The hardliners in the ERG show no desire to fall into line. Her erstwhile partners in the DUP are adamantly opposed. And any Labour MPs tempted to support her must be worried that she could be kicked out and replaced by somebody like Boris Johnson who would then go for an even harder form of Brexit.

The one way the prime minister could get her deal through is by agreeing to put it to a public vote. There would be an overwhelming majority in parliament for that. May herself may finally come to the conclusion that this is the path of least resistance – as it would cause a smaller split in the Tory party than embracing a customs union. Unlike various softer forms of Brexit, it also doesn’t contradict the last Conservative Party manifesto.

But it’s also possible that the prime minister will do what she so often does – kick the can. Just because the European Council president warned her last night not to waste the extra time doesn’t mean that she won’t try.

But MPs can stop her. They have shown this week that they can pass emergency legislation against the government’s wishes. If she dithers, they could force a referendum, perhaps even on her deal.

There is much speculation that hardline Tories will kick the the prime minister out because she has agreed another Brexit delay which will involve holding the European elections. But it’s not easy to do that since nobody can challenge her until December under Conservative Party rules.

What’s more, May is clinging onto office like a limpet – and there’s no consensus on who would take her place. The more pro-European wing of her Cabinet meanwhile seems to be rallying around “nurse, for fear of finding something worse”, to quote Hilarie Belloc.

The EU’s decision to set a new Brexit day at the end of October makes it even harder to remove the prime minister. Even if her rivals crowbar her out of office, it will be difficult to get anybody else in place soon enough to conduct meaningful talks with the EU.

Of course, one way of getting rid of May would be for her own MPs to join Labour in a vote of no-confidence against the government. But this would trigger a general election which Jeremy Hunt, the foreign secretary, rightly says would be “catastrophic” for the Tories.

One can never completely discount the possibility that some Conservatives could behave like lemmings and charge over the cliff. But even if they do, that will be good for pro-Europeans. Provided Labour pinned its colours firmly to the pro-referendum mast, we would have a good shot at getting a government committed to a public vote.

There will not be time to hold European elections, a general election and a referendum, all by the end of October. But an incoming Labour government could ask the EU for yet more time. Alternatively, it could argue that a general election gave it a mandate to cancel Brexit.

Even without throwing a general election into the mix, it will be hard to hold European elections and a referendum in six and a half months. But provided MPs decide they want to give the public the final say by early June, it should be possible.

If we need a little bit extra of time, the EU would probably agree. But we shouldn’t count on it. Last night’s European Council decision gives us a marvellous opportunity. We need to get cracking.

Hugo Dixon is chair of InFacts