The great physicist Richard Feynman warned of the perpetual torment that lies in wait for people who try to understand quantum mechanics. Modern physics cannot be understood. It can only be observed. ‘I am going to tell you what nature behaves like,’ Feynman said. ‘Do not keep saying to yourself, "but how can it be like that?" because you will get down the drain, into a blind alley from which nobody has yet escaped. Nobody knows how it can be like that.’

Equally, nobody knows how the Conservative Party can be like that. It just is. Theresa May, to pick an example. Every morning I wake up and check if she is still prime minister. Every morning the answer comes back, ‘apparently so’. She threw away a 20 per cent plus opinion poll lead and the first Conservative majority the Tories had won since 1992. I am not going to attempt to explain why she hasn’t resigned, that would be to lead you down Feynman’s drain and up his blind alley. All I can do is record what Tories say.

May is to stay in power as a human shield, they explain. She will see the Conservatives through their rough patch. The hard times over and Brexit delivered, the Tories will dispense with her and elect a new leader to defeat the Labour left and return a revitalised right to power. When they discuss this scenario, the more thoughtless Tories speak as if Brexit were some minor matter; a piece of government business that May can deliver by 2019, like a change to the benefit rules or a new bypass in Buckinghamshire. Job done, the Conservatives and the country can move on. If only.

The most important decision in recent history was not necessarily the referendum result but Theresa May’s decision to go for a hard Brexit afterwards. In her Lancaster House speech she ruled out membership of the single market and customs union. It is for this reason Lord Adonis and others, including me, compare the Brexiteers to Chamberlain and Hitler’s appeasers. They have thrown away every option except the most difficult option, and staked the house on it being right.

You can sense that the public mood is shifting. But as far as power politics are concerned nothing has changed. The Tories and Labour are as committed to a hard Brexit as they ever were. By necessity, it will be incredibly difficult to achieve. David Davis admitted that Brexit would be as ‘complicated’ as landing on the moon (although I suspect by the end it will feel as if the moon has landed on us). If you still believed it was possible to understand British politics, you would be able to point now to all kinds of evidence that the country was getting ready for the complexities ahead.

But there is next to nothing to see. While the EU has mapped out its position, the only policy Britain has produced for public discussion is its position on EU migrants in Britain and British migrants on the continent. The lack of preparedness is starting to show.

This week, the National Audit Office warned of Whitehall falling apart. It seems now we will have to pay a whopping divorce bill before we can begin trade negotiations. The payment will doubtless trouble those who believed that, far from costing money, leaving the EU would save £350 million a week for the NHS. Meanwhile, ministers are taking more power to themselves than any cabinet outside of wartime, and UK companies, terrified of being cut out of their biggest export market, are saying that they will continue to apply European standards even when we are out of the EU.

Everyone talks about Johnson and Gove’s promises to hand the NHS £350 million a week as being the big lie of 2016. To my mind, the bigger lie was the failure to explain how complicated Brexit would be. An honest leave campaign would have admitted the complexity, even trumpeted it. The extent to which the EU is tied into our lives is an argument for saying that it has too much power and we should, to coin a phrase, take back control. But the leavers stayed silent because they knew perfectly well that voters don’t want to hear that anything they vote for will be hard or expensive. As culpably Theresa May, David Davis, and in their own ways, John McDonnell and Jeremy Corbyn have maintained the illusion ever since.

Maybe it is because they fear that their opponents will reopen the EU question, if they show the smallest sign of weakness. Maybe it is because they cannot admit to themselves what they have done to Britain. Maybe…but there you go, I’m trying to explain. As with quantum particles, I can't say why they are the way they are. All I can do is describe where they have left the rest of us. And that is here.

The Tories and Labour are both split down the middle on Brexit. Neither can offer a coherent account of what Britain should do next. Unfortunately for them, and us, the clock is already ticking. For no good reason apart from party management, May began the two-year Article 50 process in March when we were even more unprepared than we are now. Meanwhile a substantial section of right-wing opinion is preparing to walk out of the EU with no deal at all. From their point of view, nationalist rejectionism makes sense. It’s just that they could take markets and the economy over a cliff edge when they do it.

'The first principle is that you must not fool yourself and you are the easiest person to fool,' said Richard Feynman in a different context. Whether leave politicians are fooling themselves I am not qualified to say. But they are certainly making fools of the rest of us.