You couldn’t make it up, you really couldn’t. Having told the nation repeatedly that with one bound we would be free to “take back control” of our own future, it turns out that the Brexiters haven’t the faintest clue about what the future holds. None. Zip. They have persuaded the nation to jump out of a plane without parachutes — and they have no idea how to avoid a crash landing.

Worse still, what they did tell us about the future turns out to be false too: Nigel Farage now admits that the infamous claim that we would have £350 million a week to spend on the NHS should never have been made; Daniel Hannan asserts, with a straight face, that Leave never really claimed immigration should be significantly reduced; and Brexiters have assured the Northern Irish that there will be no checks at the new land border with the EU.

So there we have it: no money saved, no major cut in immigration, no control over our border with the EU.

Boy, would I feel double-crossed if I was one of the millions of people who voted for Brexit because I thought we would get all three. The wrath of betrayal which awaits Brexiters will make the anger directed at me over tuition fees look like a Sunday school picnic. Two big things immediately follow from this mountainous act of deception.

First, the victors must come before Parliament within the next week to tell us all what they want us to do next. Shrugging their shoulders and wittering about the need for time, as Boris Johnson has done, is intolerable. He, Michael Gove and Gisela Stuart — the leading Brexit MPs — have won. Now comes the responsibility of victory.

If they have a plan, we need to hear it. Do they want to be in the single market or not? When will they trigger Article 50? What kind of points-based immigration system do they want? How will they retain the City’s “passported” access to European financial markets? How will they cope with the UK’s ballooning current account deficit, now larger than at any time since records began? Which taxes will go up and what spending will go down?

As a legislator in a Parliament facing reams of new laws to replace what we’ve chosen to tear up, I urgently need answers to these problems if I am to do my democratic duty.

It seems that some of the leading Brexiters never imagined they might win: it was all a bit of a game, protest politics at its worst. Tough. They’ve won, and now it’s their time to decide and lead.

Second, there will have to be a general election shortly after the new Conservative leader is elected. The country did not elect a Brexit government last year. The millions of voters who gave David Cameron the benefit of the doubt did so, above all, because they were worried what would happen to the economy if Ed Miliband and Alex Salmond were in charge.

Well, now they’ve got something they never bargained for: a reverse coup within the Conservative Party of hardline Eurosceptics backed by unaccountable vested interests in the press whose actions are already wreaking havoc within global markets. The price of petrol will soon rise because of the plummeting pound. Pensioners’ savings are worth a lot less than they were last week. Investment decisions have evaporated. Uncertainty abounds.

So it is inconceivable that the British people should accept a new Prime Minister just because he or she emerges like a cuckoo in the nest from an internal Conservative Party contest. The voters who will elect our next Prime Minister — Conservative Party members — constitute just 0.003 per cent of the electorate. Once they’ve had their say, it will obviously be the turn of the remaining 99.997 per cent to choose a new government.

For that is what it will unambiguously be: a new Government, run by new people, in a new reality, with new plans that depart dramatically from the government elected last year.

And when we vote in that general election, the key question will be this: do we agree or not to the terms of our exit from the EU? Since the Brexiters refused to give us any clue before last week’s referendum, they should be given the opportunity to put their plans to the British people.

My guess — judging from conversations I’ve had with European leaders in the past few days — is that Gove, Johnson et al will be taken aback by the unsentimental attitude of other EU countries. Their markets have been hit hard by the Brexit vote. They can’t afford further economic turmoil in their own countries. So they’ll want to cut their losses and will be in no mood to cut a sweetheart deal with Brexiters who are generating so much economic turbulence across the continent.

In the end, I suspect the choice will be stark: if Brexiters want to maintain access to the single market, it will come at a price, as it does for countries such as Norway, Switzerland and Iceland. The exact terms of our exit will determine everything from our ability to export steel widgets to the visas we need to go on holiday; from the future of car plants in the North-East to fishing rights in the South-West; from the recruitment of nurses in the NHS to the databases our security services use to track terrorists; and how much money and rule-making authority we are prepared to concede in order to keep open trade access to the rest of Europe has a direct bearing on our own constitutional governance too.

So the exact terms of our exit is no technical matter. It should be up to us — the voters — to make that final choice, not a small cabal of Brexiters in Westminster. The Brexiters have won the argument in a referendum to exit the EU. They have not, however, secured a mandate on how that should happen.