Why on earth do we run ourselves down so much? A presumption of inferiority, incompetence, decline, failure, humiliation and catastrophe saps our politics.

UKIP is a party dedicated to the proposition that everything has got worse since the 1950s. The Corbynistas are convinced that things in the Labour Party went wrong at the latest in 1983, when Neil Kinnock became leader.

And during the EU Referendum, this propensity to run ourselves down became the driving force of the campaign, with each side denouncing the other in unmeasured terms. The fact that (as we were told) this was a one-off contest, which each side felt it had to win, meant there appeared to be no reason to hold back.

So no prominent figures on either side admitted there might be something in their opponents’ arguments, or expressed the dilemma of floating voters who could see merit both in the view that it is more democratic to run our own affairs as a sovereign nation, and in the contention that we cannot be indifferent to future developments on the continent of Europe, so ought as a matter of common prudence and decency to remain members of the European Union.

We instead found ourselves assaulted by both sides with speculative assertions about the economy which were presented as matters of unquestionable fact. The more one listened to these forecasts, the less one felt one knew about the balance of advantage, for the insulting assumption was that as voters, we were not merely venal, but extremely dim.

You may recall the dreadfully repetitive argument about the number on the outside of the Leave bus. Exposing this figure as a lie was felt to be a sufficient argument against Brexit, for this must demonstrate that Boris Johnson and Michael Gove were such despicable people they could not be trusted with anything.

Ad hominem attack supplanted any consideration of the principles of British foreign policy, and to what extent these can be reconciled with the principles which inform the British constitution. When Boris Johnson was found to have drafted two articles, one in favour of Remain and one in favour of Leave, he was regarded, not as a sane and balanced person who could see merit on both sides of the argument, but as a shameless opportunist who did not believe a word he was saying.

For Remainers, all seemed lost on the night of 23rd June 2016, when it emerged that the Leave side had unexpectedly won the referendum. This led to a great outpouring of anger and hatred not just against Johnson, but against Leave voters, who were denounced as ignorant, backward, racist, flag-waving Little Englanders.

Every kind of barbarity was imputed to them. It was all their fault when foreigners were abused in the street. European civilisation, and European peace, clearly meant nothing to the Leavers, who were so stupid and malign they had also voted to destroy their own jobs by wrecking the British economy.

And every kind of incompetence was attributed to the British Government. As Paul Goodman observed on this site yesterday:

“A dominant narrative in our culture is that British politicians are useless – one shared by some on the right, especially at the crossover point where the Conservative and UKIP activists meet, and some on the left, notably in the Remain coalition for which belief that the Government has bungled the negotiation has become an article of faith.

“On the contrary, the deal shows, as its outlines come into view, that the Prime Minister has got much of what she wanted – including on money.”

Many, perhaps most, Londoners expected the 2012 Olympic Games would be a dreadful embarrassment, blighted by the inability of British politicians to do anything right. The press assumed the story would be of transport and other arrangements going disastrously wrong.

Instead the games went off wonderfully well, for the politicians and administrators who were running the show had learned from mistakes made by other Olympic hosts, and many years of investment were at long last resulting in frequent and reliable trains and buses in London.

When I wrote a volume of brief lives of all 54 British prime ministers from Walpole to May, I lazily assumed quite a few of them would turn out to be duds. But although many of them ended up as failures, very few of them were either stupid or crooked. For in order to be prime minister, you have to command a majority in the House of Commons, which can tell within about three seconds of your standing up to speak if you are incurably thick, and can usually detect dishonesty too. David Lloyd George did not last long after becoming notorious for selling honours.

Donald Trump would have stood no chance of persuading MPs he was a fit and proper person to become Prime Minister. One of the many admirable features of the first past the post system is that Nigel Farage has not even managed to become an MP. Demagogues have never thrived at Westminster.

I refuse, by the way, to regard Sir Robert Walpole as a crook, just because he managed to build a palatial mansion, Houghton Hall, from the proceeds of public office, and gave valuable posts to his family. That was how things worked at that time, and he was abused by the best writers.

Another great advantage of parliamentary politics is the convention, which at first sight may seem merely quaint, that Members are Honourable. Under the rules of the House, they cannot dismiss their opponents as criminals or liars, for the excellent reason that to hold a debate with someone you dismiss as a criminal or a liar is impossible.

British public life includes a wonderful tradition of abuse, upheld at its finest by our caricaturists. But at general elections, the main candidates usually exercise a degree of restraint, for fear of alienating undecided voters. Churchill’s “Gestapo” attack on Labour during the 1945 election was generally reckoned to be a mistake not just in terms of taste, but in terms of votes – a verdict some historians dispute, but with which his most recent biographer, Andrew Roberts, concurs.

The presumption of incompetence which we attach to our politicians is a valuable safeguard against disappointment, and against respecting them too much. A free people needs, if anything, to err on the side of disrespecting its leaders too much.

But there has been a tendency, since the start of the 20th century, to suppose that because Britain’s power has declined in relative terms (a development which was inevitable, once our competitors industrialised), our politicians must also have declined in quality, and must have become, in fact, totally useless.

That is unfair. They are, in general, no more useless than they ever were, and many of the public services for which they are responsible work rather well. We wait each winter for a crisis in the NHS, and perhaps this year we shall get one, but in most respects that service has become better.

A healthy suspicion of the state ought not to spill over into the conviction that it and its servants are totally useless. Otherwise why bother?