The British public deserve to know the whole truth about Britain's position in the Brexit negotiations

Angela Merkel has accused Britain as having 'illusions' about Brexit: EPA

The Brexit negotiations have hardly begun, and have already broken down. That is not too alarmist a verdict on what appear to be reliable reports about the informal discussions over dinner between Theresa May and Jean-Claude Juncker, President of the European Commission.

According to these accounts, and public remarks by the German Chancellor Angela Merkel, the British Government is entirely deluded about what to expect from the talks. Ms May is labouring under the illusion that she has bargaining power and that that power will be greatly enhanced if she wins a landslide victory in her unnecessary and premature general election. That is a blunder almost as historic as David Cameron's when he pledged an in/out referendum. It will lead to national disaster.

The Europeans are making it as clear as they can within diplomatic conventions that the British have very few cards to play, and the EU negotiators aren't much interested in the make up of the House of Commons.

So Ms May's bluff is being called, and the realities behind the diplomacy of Brexit are coming into focus. Europe is the world's largest trading and economic bloc. The UK is a great trading nation that earns an uncomfortably high proportion of its living from trade and investment with the continent. We need them more than they need us. That is the fundamental truth about the balance of power.

A rational deal advantageous to both sides, which is to say superior to the status quo, is impossible, because no possible terms can be better than the single market regime. A deal that is better than no deal is possible, and desirable, and mutually beneficial – but not inevitable.

The dream of the hard Brexiteers and the nightmare of the Remainers is identical: the UK crashes out of the EU, has to adjust to whatever Europe decides, and tours the globe looking for deals with nations from the US to South Korea who are prioritising the EU. No amount of fantasy about a second Elizabethan era of buccaneering entrepreneurs winning new export markets will compensate for the migration of the car industry, aerospace, food processing and the City to the rest of the EU or elsewhere in the world. Communities will lose jobs, investment will collapse and Britain will recede into being the sick man of Europe as it was before joining the EU in 1973.

It takes two, in other words, to make a deal and if the EU is as united and clear in its objectives as it seems, and with the economic and political muscle to back that up, then, as has been made clear, the UK will be lucky to get the kind of limited deal Canada obtained after a decade of wrangling. To be fair to the Prime Minister, it seems to be that it is the EU Commission that is making future arrangements for EU citizens in the UK more difficult than needs be, but that merely demonstrates who wields the power in the EU-UK relationship. It also makes the case for an open and unilateral offer of full rights to those people more compelling.

That, as they say, is the big picture. But these developments shed light on other non-trivial matters. It is plain that, whatever Theresa May and David Davis may desire, these talks are not going to be kept secret, and it is shameful that the Frankfurter Allgemeine Zeitung knows more about what is going on than do the British people in the middle of a general election. It is something the new Commons should find intolerable.

Brexit is increasingly meaning hard Brexit. If that is what this election is really about then the Prime Minister should say so. If not then she cannot take what happens on 8 June as any kind of mandate for her position and in any case she must offer the British people a say on the eventual terms of Brexit. If they are going to be as mean as they look now, then few in full possession of the facts would vote to leave, even if they'd grudgingly agree to have her in No 10. She needs to come clean with the people. Now is the time.