Brexiters are blaming EU “bullies” for Theresa May’s miserable deal. This is rich, since they’ve been at the heart of this mess since day one. Their fantastical demands and the strategic missteps the prime minister has made at their behest are the real culprits.

The first reason the UK looks to have got such a bum deal is that Brexiters set expectations for these negotiations so high in 2016. They insisted that we’d get a good deal because the EU needs us more than we need them. And that we could have as good a deal outside the EU as we do inside it. Both are fundamentally wrong.

Then there are the mistakes made by the government in the past two years of negotiations. Don’t forget, prominent Leave campaigners have been ministers in that government throughout – and Brexiters outside the Cabinet have been hounding the prime minister to do their bidding.

The biggest mistake was triggering Article 50 without a proper plan or achievable goals. That meant months of refusing to budge on unworkable, contradictory red lines before inevitably caving in to the EU’s proposals. And again, those red lines can be traced directly back to what Brexiters promised in 2016.

Then the government agreed to a “backstop” insurance policy to keep the Irish border open. It’s now clear this could easily lock us into a miserable, rule-taking relationship with the EU – potentially indefinitely. But because the government had no plan, the EU proposal was the only one on the table. The Cabinet which first agreed to this last December was full of Brexiters – including Boris Johnson and David Davis – who clearly didn’t take the time to understand what they were signing up to.

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Now May is making another error. She’s pushing for a “blindfold” Brexit where we sort out the details of Brexit after we’ve left. This helps her cover up how terrible her deal will eventually be. But after we’ve left the bloc – having made binding commitments to pay lots of money and keep the Irish border open – we’ll have even less leverage, because every single EU country will have a veto.

That is likely to see our “divorce bill” balloon from May’s conservative £39 billion estimate to more like £60-70 billion if we need to extend the post-Brexit transition period beyond 2020. It also means individual EU countries can push their terms for a future trade deal – whether that’s more rule-taking, access to UK fishing waters, or more Spanish influence over Gibraltar.

Throughout this negotiation process, the EU has said it wants to be “fair”. But unlike our government, EU officials have been realistic. They know any Brexit will be damaging, but accept the UK voted to leave. Of course, fairness towards Britain can only go so far when it starts hurting the interests of the remaining 27 member states and the European project as a whole.

It was always impossible to deliver the Brexiters’ fantasies. However, we already have a good deal inside the EU that doesn’t need negotiating. That’s why we need a People’s Vote, to ask the public if they want to throw what we’ve got away in favour of May’s Brexit mess.

Edited by Hugo Dixon