May must go. But which of the wannabe-Winstons waiting in the wings is up to taking over?

This may be the moment of truth, but it is only the truth of the moment. The vote of confidence this evening may make or break the Government. A change of prime minister in the midst of a crisis does not always elicit the kind of morale boost that Churchill delivered in May 1940 when he took over from Chamberlain. In retrospect, the 48 Brexiteers may be seen to have done the right thing for the country by putting Theresa May out of her misery. But they are also risking the possibility that Brexit won’t happen at all.

If only the 48 Brexiteers and the rest of the Tory rebels really did resemble D’Artagnon and his three musketeers. “All for one and one for all”, the musketeers’ motto, hardly applies to this fissiparous fronde. United only by their determination to bring down the Prime Minister, they are already manoeuvring even before she has gone.

Go she must, however, if the Conservative and Unionist Party is ever to reunite around a single kind of politics, let alone policy — on Brexit or anything else. The rancour is now worse even than in the early 1990s after the assassination of Margaret Thatcher and the subsequent split over the Maastricht Treaty. Some of the leadership candidates this time can scarcely remember that feud, more than quarter of a century ago. But the bitter legacy it left behind has been passed on to the next generation. Tonight’s spectacle and the gladiatorial contest that will doubtless follow are the latest gory consequences of a tragic failure to resolve the conflict over our island’s relationship with the Continent.

Not the least regrettable aspect of the affair is that our nation can only be a spectator at the showdown which will decide our fate. At least the Tories aren’t wasting time. Mrs May deserves an end with horror rather than a horror without end.

Who, though, will play the part of Churchill? One of the many ways in which that particular historical analogy does not apply here is that he faced no serious rival. As Lord Halifax, the then Foreign Secretary, admitted himself, it would have been unthinkable to have a national leader who was confined to the House of Lords and hence only indirectly accountable to the Commons. It did not seem to occur to anybody to alter the rules; that would just not have been cricket. So Churchill had the field to himself. That made his emergence at the right moment seem providential.

Today we have far too many Winston-wannabes: there are at least a dozen aspirants who think themselves better qualified than Mrs May, not one of whom has held high office for anything like as long as she has. Churchill, let us remember, had held two of the great offices of state (Home Office and Treasury) as well as twice running the Royal Navy (as First Lord of the Admiralty), the Army (as Minister of War), the Royal Air Force (as Minister of Air) and the war effort (as Minister of Munitions). Nobody could possibly have been better equipped to win the Second World War. What exactly did any of the present Tory hopefuls do?

Boris tells us that he has lost 12 lb in two weeks: “If I can do it, so can we all.” Well, he will have to do a lot better than that. His loss of nerve during his last leadership bid has never been forgotten and cast a shadow over his modest accomplishments as Foreign Secretary. At least everyone knows who Boris is. But Dominic Raab? His tenure as Brexit Secretary was over almost before it had begun. Sajid Javid has done well as Home Secretary, but he has only had the job since April and entered the Cabinet less than four years ago. And Michael Gove? The most successful minister in the Cameron Coalition, without a doubt — but a mercurial and mysterious man, mistrusted by many.

There is certainly no shortage of dark horses: Geoffrey Cox, who roused the last party conference; Priti Patel, as feisty as they come; Amber Rudd, a Mrs May without the baggage. But David Davis should not be ruled out. His biggest advantage is his age: he will turn 70 on December 23 and so would be the ideal caretaker to deliver Brexit before handing over to a younger leader before the next election.

Future generations may look back on this day and wonder what we thought we were doing. But one of the great strengths of the British constitution is that the Prime Minister can be replaced painlessly and at short notice. It is at least an improvement on the kind of revolution we are witnessing across the Channel.