I meet Bernard-Henri Lévy in a colossally luxurious hotel on a tree-lined avenue just behind the Elysée Palace. The French philosopher is half-reclining on a sofa, with one ankle tucked under his thigh, beneath an ornamental bookcase bearing a bust of Voltaire. He wants to discuss his new play, Last Exit Before Brexit, which will receive its world premiere at Cadogan Hall, London, on 4 June, under the auspices of the Hexagon Society. The play takes the form of a 100-minute monologue. What’s it about?

‘A group of anti-Brexit intellectuals decide to organise a last-chance event in the symbolic city of Sarajevo. They ask me to deliver the keynote speech. And I, or the character of the play, is enclosed between the four walls of his hotel room, trying to prepare his speech, but the text escapes through his fingers, it disaggregates itself, it flies away. Why? Because the very object of his speech, Europe, is a ghost of itself. And this is unacceptable. This is unbearable. The play is a call for the resurrection of Europe, a call for Europe to gather back its spirit. It’s a call for Remain.’

Londoners will love it, I tell him, because most of them voted against Brexit. This dismays him. He’d prefer to perform to a pro-Brexit crowd in the hope of changing their minds.

‘I want them to react, to be shocked, to scream!’ In that case he should take his message beyond the M25 and into the Brexit heartlands. ‘I hope I will be invited to perform it outside London. Perhaps you can say that in your article. I’m available.’ Who does he blame for Brexit? Britain or the EU?

‘Both. This is what my play says.’ He castigates the European institutions for building an ‘empty machine’ and a bureaucracy which he calls ‘a disgrace’.

‘You should not be surprised when the people, especially one of the most important [of European] peoples, turn their backs.’

He adds that ‘a huge responsibility lies with the leadership of the Brexit camp: their lies, their vulgarity. But you cannot always blame institutions and leadership. You also have to blame the people. In France when Marine Le Pen stands at the gates of power, I blame the people. And in England the responsibility lies with the people.’

Was it xenophobia? ‘For sure. All kinds of xenophobia and anti-Semitism on the right and on the left. On the left now [especially] strongly. Jeremy Corbyn, and Livingstone before [him]. Deep in the Labour party you have a growing anti-Semitism. If you put all that in the shaker — xenophobia, anti-Semitism, populism — you have the cocktail which is part of what makes Brexit possible.’

I offer a précis of Brexit’s causes from the Leave perspective. ‘In 1973 we joined a common market, but the EU has now turned into a super-state. To the British, it looks like an attempt to recreate the mission of Napoleon, of Hitler, of Julius Caesar, of the Catholic church. And Britain rejects that.’

‘Disgusting’ is his response to this. ‘Napoleon was a killer and a dictator. Hitler was a monster. To compare the leaders of Brussels to these two people today is not responsible. Mr Farage would speak like that.’

He chose London for the play’s première because he regards Britain (or ‘England’, as he sometimes terms the UK) as the ‘beating heart of the European project’. ‘It is not just an additional piece. It is the main part of the DNA. Without England, Europe will be not Europe, it will be something else.’

But if Britain was Europe’s ‘beating heart’, why did De Gaulle prevent our accession? ‘He was not European. He was anti-Europe. And Europe began to be built when English thought, which is liberalism, the doctrine of the open society, the spirit of Keynes, Popper, Adam Smith and others, was embedded in the European project. When Europeans decided to integrate English ideology in their project then the dream began to take flesh, and to take shape.’

He heaps more praise on Britain and says that British military action ‘saved Europe from suicide two times, if not three, in the 20th century. The world wars, and in Bosnia-Herzegovina, Sarajevo, which is so dear to my heart’.

He’s convinced that Brexit will be a terminal event for the EU. ‘If Brexit happens, Europe will collapse. It cannot survive Brexit. In France everybody believes Europe can survive. It’s a big mistake.’

And which country will be next through the escape hatch?

‘I don’t know. After Brexit, the idea of leaving would be in the head of each of them. No one will want to be the first. So there will be a strange game. It will take some time.’

For him, the disaster of Brexit served the interests of two men. ‘Not Farage, not Boris Johnson. This is a petty victory for them, but it was a great victory for Putin and for Trump. And England is too great a country, with too great a culture, with too great a responsibility in the world, to be played as a marionette in the hands of Putin and Trump. But that’s the situation.’

Then he confounds me with another prediction. ‘I can tell you this. Brexit will not happen.’

How come?

‘Somehow,’ he says. ‘History has more imagination than us. It is a law. All the important events in history happen despite speculation, despite possible hypotheses. History always disavows the most [likely] hypothesis. It always [turns out to be] something else.’

I suggest that Brexit is pretty heavily inked in for March 2019. Does he imagine that Britain might re-join five years later?

‘We’ll see. Let’s take a bet, you and me.’

I suggest to him that if his view of Britain as the moral cornerstone of the EU had been better promoted during the campaign, Brexit might not have happened.

‘It hasn’t yet. It’s not too late!’

And he seems perfectly sincere in these three astonishing prophecies. The EU will collapse without Britain. Brexit must be prevented. And the reversal will be led by him.