Any fool can see, as Sue Gray put it in her “update” published yesterday, that the No 10 parties were the result of “failures of leadership and judgment”. The question is not whether those failures occurred, but whether they are unforgivable.

And that is not a question which can be left either to Gray, or to the Metropolitan Police. It is a question for politicians.

If one is an Opposition MP, the answer is obvious. According to Sir Keir Starmer and Ian Blackford, the Number Ten parties mean Boris Johnson must go.

To the rest of us, the answer depends not on the details of the parties, but on our instinctive sense of right and wrong.

If is not difficult to rationalise condemnation of the Prime Minister, or, if one prefers, mercy. One may, if one wishes, clamber onto one’s high horse, and declare in high-minded tones (cf the Profumo affair) that it is a moral issue.

Much pleasure can be derived from this approach. A warm feeling of self-righteousness courses through one’s veins. How wonderful to be so superior to Johnson. Public life must be purified by casting him into outer darkness.

The other approach, which is the one Johnson himself would take in normal times, is to regard such casting of anathemas as so much humbug, of a kind which comes easily enough to our proud, pious, latter day Puritans, but which anyone with a scintilla of humility should resist.

Yes, there were failures. But who will cast the first stone?

There is something repulsive about presenting oneself as so noble and incorruptible that one can gaze down from a great height on the wicked people in Downing Street, and can condemn Johnson as the wickedest person of all.

That he, and they, got things wrong cannot be denied. They were mortal. They felt sometimes in need of a drink at the end of a long day making life and death decisions where it was easy to arrive at the wrong answer, and to be exposed within a short time as having got it wrong.

Do we imagine that if no drink had been taken within Downing Street, the decisions would have been any better? What a prosy and preposterous proposition.

Behind the criticisms of Johnson lurks an implausible idea of perfection. Immaculate behaviour – no parties, no drink, no cake – would have led to immaculate decisions and an immaculate Prime Minister.

What humbug, what hypocrisy. There never has been a perfect Prime Minister, and never will be. We have to take the least bad Prime Minister on offer. Many people still consider that to be Johnson, when one looks at the various pallid alternatives.

Do we really want, at this moment, to start training up a new Prime Minister? As freeborn Britons we possess, of course, a perfect right to chuck whoever happens to be Prime Minister overboard whenever we wish.

We are not in the appalling position of the Americans, who have fixed terms for their presidents, and have therefore felt driven to impeach or assassinate those of whom they have tired.

Incidentally, many of our best politicians, and best writers, have drunk too much, or what a prude would consider too much.

Would Pitt the Younger have been able to stand up to Napoleon on less than three bottles of port a day?

Percipient readers may already have guessed that this article has been written with the help of some modest amount of alcohol. If the author had been sober, the article would have been duller.

On the other hand, if the author had drunk more than half a bottle of red wine, and a glass of whisky, the article would have been very much better.