In the old days, if the Tory party was in trouble, old hands who had seen it all before would attempt to steady the buffs with a traditional rallying-cry: ‘pro bono publico – no bloody panico.’ Today, that message is needed as never before, but would the MPs take any notice? In the nineteenth century, an Irish Parliamentarian lamented that: ‘Ireland’s cup of troubles is overflowing – and it is not yet full.’ For Ireland, read the Tory party.

It seems quite likely that on Thursday, the Tories will come fifth in the Euro elections, behind the Brexit Party, Labour, the Liberals and the Greens, struggling to get into double figures in percentage terms. That would be the worst result for either of the two leading parties in British political history.

In the aftermath, there will be a lot of panic. A lot of MPs will be worried about their own seats. Others, even if they personally feel safe, will fear for the country under a Corbyn government. But there is an analogy between a Tory politician and a drowning man. A poor swimmer realises that he is out of his depth. There is only one way to survive: stay calm, muster his strength and try to reach safer water. If he panics, he drowns. The worse the result on Thursday, the greater the need for calm and deliberation.

As for a Corbyn government, there may be some comfort for the Tories. They are not the only ones who will do badly in these elections. An opposition party with a realistic chance of forming a government ought to perform extremely well in any mid-term contest. That will not be true of Jeremy Corbyn. The best he can hope for is a bad second and he could even fall back to third place, behind the Liberals.

There is a further point. Corbyn is an educationally-limited, anti-Semitic hard-left Socialist. None of that is going to change. Under a Brexit deal and a new leader, the Tories could stage a rapid recovery. There is no Labour equivalent. Some of them dream about displacing Corbyn but given their electoral system that is virtually impossible. The Momentum movement which swept him to power has not lost its momentum.

Returning to the Tories and the Brexit deal, the best hope for its supporters is that it is not yet dead. Unlikely, certainly, but it is still just too early to switch off the life-support machine.

In the case of the Leader, that machine was switched off months ago but May has not yet noticed.

Then we come to her successor, which leads straight on to the perils of panic. Boris Johnson has emerged as the favourite for the succession, to which there is only one reasonable response: why? What has Johnson ever done to suggest that he has the moral or intellectual depth necessary to be prime minister: the patriotism and love of country necessary to be a Tory prime minister?

He once summarised his own political – and personal – philosophy: ‘Have cake, eat cake.’ The country is facing the gravest domestic political crisis since the Great Reform Bill in the early 1830s. This is no time for a leader who could not even run a cake stall.

So why does he attract support? Well, he makes people laugh. If you believe that this is a time for clowning, by all means support Boris and prepare to laugh on the other side of your face. Some other older Tory supporters who think that they do know the difference between a circus and a government are disillusioned with the current run of politicians. They are looking for someone with stature. Stature? Boris? We are back in the circus.

One of Boris’s advantages is that he believes in nothing except himself. As he has no intellectual baggage, he can skim lightly across the surface of politics. In one of the ‘Just William’ books, William Brown – a character whom Boris resembles – announces that he would like to be King. A member of his gang asks him what he would do if he were King. ‘I would rule,’ replies William. William was eleven years old. Boris, who has at least reached puberty, would also rule, until the cake ran out after five minutes.

What, for instance, would he do on Europe? He will no doubt promise to negotiate more effectively than May. That should not be hard, but it would be for Boris, who would have two weaknesses.

First, the Europeans would be most reluctant to give him a better deal than the one May was offered. Second, Boris was a hopeless foreign secretary. Few foreigners whom he dealt with took him seriously. The idea that he could suddenly transform himself into a consummate diplomat – time for another slice of cake.

So what happens then? A hard Brexit? He would not have the votes in Parliament. Some Remainers are almost tempted to support Boris, because they think that he could be forced into a second referendum. With him in charge, Brexit could lose.

There is of course another obvious outcome: a general election after Boris’s government has disintegrated, with Nigel Farage still very much on the scene, promising that he will deliver a bigger helping of cake. A Boris premiership would quickly turn a car crash into a train crash followed by a plane crash, otherwise known as a Corbyn government. There might be some relief in this for Theresa May. She is about to go down in history as the worst prime minister since Goderich. But Boris Johnson would displace her.

The Tory party is full of sound potential prime ministers, waiting to recapture the great Tory theme of aspiration, to expound attractive policies on housing, to offer economic stability, to restore national morale.

In comparison, Boris would be a snare and a delusion, a fantasy: a disaster. I have already quoted Philip Stephens of the Financial Times. ‘Boris Johnson has lied his way through life and politics.’ Anyone tempted to join Boris around the cake plates should ponder those words.