People hold placards during a rally in London. File/ AFP

The second extension to the Brexit deadline agreed by EU leaders makes it likely that we will never leave the EU. There are two questions about the new deadline of 31 October.  Will the House of Commons vote for a deal by then? The answer to that is probably no. And will the EU allow a further extension after Halloween? The answer to that is probably yes.

The last time Theresa May tried to get her deal through parliament she was 30 votes short of the majority she needed. Since then at least one Conservative MP, Richard Drax, has decided that he was wrong to vote for her deal and says he would not vote for it again. She seems to have given up trying to persuade her Northern Irish partners in the DUP, so she needs at least 31 Labour MPs to support her deal.

However, it is hard to see why it would be in Jeremy Corbyn’s interest to give her that support. The talks between the government and the opposition serve a purpose for Corbyn in presenting him as a national leader prepared to engage in dialogue, but he does not want to agree a Brexit deal. It would upset many Labour Party members and voters if he ended up facilitating Britain’s exit from the EU. Even his most ardent supporters would question his aiding a Tory prime minister.

So I don’t think the talks will come to anything. The prime minister can try to persuade Labour MPs to support a deal without Corbyn’s blessing – which doesn’t count for much with many of them – but they have proved resolutely unpersuadable so far. Two weeks ago, only five Labour MPs (and two former Labour MPs, Ian Austin and Frank Field) voted for the withdrawal agreement.

More Labour MPs might be tempted in the next few weeks by the prospect of cancelling the European Parliament elections, but they are unlikely to be blamed individually by their Leaver constituents if the elections go ahead.

So what else is going to change over the next six months? The Conservatives might have a leadership election, although a spokesperson for May made it clear that she does not intend to go unless she gets her deal through. Her MPs might get rid of her anyway. The rules of the 1922 Committee, which represents backbench Tory MPs, prevent another challenge to her leadership for a year since the last one in December. But those rules can, of course, be changed by backbench Tory MPs.

Yet if she were to be replaced, presumably by a candidate advocating leaving the EU without a deal, that new prime minister would still be unable to get that proposition through the Commons. And, as Yvette Cooper has shown, the Commons can legislate to frustrate it.

So if by October the UK is still a member of the EU, what then? The other EU leaders, having granted an extension twice, would be most likely to do so again. Emmanuel Macron might huff and puff, but on Wednesday night he was persuaded to go along with the consensus view for a long extension. The same arguments will apply next time. The EU will not want to be blamed for forcing a no-deal Brexit – not least because of the economic damage that it would do to Ireland, with whom all member states have declared undying solidarity.

They will be sick of the endless arguments about Brexit, but it will be six months since the last series of late-night crisis summits and other problems will have absorbed their attention. They will put the cause of European unity first and say to themselves, again, that if the British cannot sort out their own political system, they will make a show of strategic tolerance.

And we British have shown, as the anonymous legal blogger, Spinning Hugo, has argued, that it may not be possible to leave the EU at all under our current political system.

Both main parties are divided: the Conservatives have their no-dealer wing that won’t vote for compromise, and Labour has its pro-EU wing that won’t vote for any kind of Brexit. And neither party will vote in sufficient numbers for a Brexit proposed by the other.

I predict that we will still be in the EU in 2020.