Pro-Europeans shouldn’t cheer Theresa May’s deal. She is signing up for the worst of all worlds: turning us into a vassal state but not even getting single market membership in return.

There is understandable relief from sensible Tory MPs, business and the Scottish government because the Brexit extremists haven’t yet managed to blow up the talks. But they shouldn’t kid themselves that the prime minister is heading for a soft Brexit where we keep most let alone all of the benefits of the single market. She isn’t doing anything of the sort.

May has merely signed up to “full alignment” of a vast swathe of our rules with those of the EU, if she can’t find some other wheeze to avoid a hard border in Ireland. Mind you, it’s not even clear she will be true to her word – given her new “nothing is agreed until everything is agreed” mantra and attempts by David Davis and Michael Gove to suggest we have all sorts of way to wriggle out of Friday’s deal.

Copying and pasting EU rules until long after the cows have come home won’t be remotely enough to keep full access to a market which accounts for half our trade. The Tories would need to cross three more of their red lines to get that – free movement, payments to the EU and the European Court of Justice’s involvement, all in perpetuity.

Labour might be willing to agree to that. Keir Starmer, its Brexit spokesperson, came pretty close to saying he would at the weekend. But there’s no way this government could do the same. The Brexit extremists would have May’s guts for garters.

The best we’ll end up with is something like the deal Canada has with the EU. Canada may sound like a lovely place where the Queen is head of state, Meghan Markle lived for years before she hitched up with Prince Harry and most people speak English. But a Canada-style trade deal would be bad for Britain. We’d get little access to the EU for our world-beating services industries. It would be a “disaster for Britain’s workers”, as Frances O’Grady, head of the TUC, wrote today.

What’s more, by signing up to regulatory alignment with the EU, we would hamstring our ability to cut free trade deals with the rest of the world. And that’s even without mentioning the blow to national pride from taking diktats, whereas up to now we’ve been one of the most influential rule-makers in the EU. How’s that taking back control?

We are in such a dreadful situation in part because Brexit was based on the false premise that the EU needs us more than we need it – when it’s exactly the opposite. But it’s also because the prime minister has botched the Brexit process every step of the way.

Rather than cheering her latest misstep, pro-Europeans should strain every sinew to stop Brexit before it’s too late.

Edited by Luke Lythgoe