If a people repeatedly tell themselves lies about what they are and were, then a sorry reckoning invariably awaits them.
I have said this many, many times about Ireland and our addictive revisits to the poisoned well that is 1916. But today, in the aftermath of its team's abominable performance against Germany, I am focusing on England.
An absurd, almost imbecilic media optimism has been the backing track to every England soccer campaign for more than a generation, but this year it was combined with a revival of the Churchillian myths of 1940.
If you tell untruths to yourself about the easily visible truths of your past, then you'll probably tell even greater falsehoods about your still invisible near-future. For the English, there is a connecting skein: namely, a wholly unjustified optimism, which is recycled so often that it must be presumed to be a national characteristic.
Now, contrary to everything that you might read in the British media, Hitler had no intention of invading England in 1940. The Battle of Britain was merely a murderous bluff to bring Churchill's government to the negotiating table. Germany had neither the intention nor the means to invade Britain, never mind conquer it.
In fact, Hitler rather admired the British empire, and what the British had done to Saskatchewan he had in mind for the Ukraine.
To be sure, the plain folk of Britain didn't know that then and they clearly still don't. Comparable ignorance informs so much of the English perception of the world today.
The British fought on in 1940 in order to save the Jews? But not even British Jews believed that the Nazis intended genocide. How else can you explain the low level of Jewish recruitment into the British armed forces during the war?
Jews - before the creation of Israel - were a very non-martial people. During the war, more British Cohens died as civilians than as soldiers. A total of 142 Cohens were killed by enemy action: 54 civilians, compared to 47 soldiers, and the remaining 41 casualties were airmen or seamen. But nearly five times more Smiths died as soldiers than as civilians. Which roughly means that, proportionately, over six times more Smiths than Cohens were killed serving as soldiers.
The statistics of army deaths for the names Brown, Jones and Murphy are roughly similar to the Smiths. Clearly, if British Jews really believed in 1940 that the Nazis planned a Holocaust, then the Jewish army recruitment figures would have been far higher. So it might be argued that stubborn stupidity, rather than principle, was why the British kept fighting in 1940.
On the day of the England-Germany match, the Sunday Telegraph carried a supplement celebrating the 70th anniversary of the Battle of Britain. It also included a quiz about English/German achievements in the past century.
Obviously, the questions were weighted in favour of the English, yet the answers were generally either wrong or misleading. Viz: In which battles on African soil did British troops not defeat a German army? A) Omdurman, B) Medenine C) Alamein.
This tasteless trinity actually says rather more about the stubborn stupidity of the people who concocted it than it does about history.
So, Omdurman - in Sudan in 1898 - was the exception, but what an exception. It was a wholly British imperial horror, in which about 20,000 tribesmen with muskets were massacred - with, you might say, almost Germanic efficiency - for the loss of about 34 British soldiers. The other two were 'British' defeats of Germans. Except that New Zealanders and Free French were a primary element in the defeat of German-Italian forces at Medenine, in Tunisia, in 1943. And the 'British' infantry in the defeat of Rommel's largely Italian army at El Alamein in 1942 were mainly from Australia and New Zealand. In other words, the British weren't British and the Germans weren't German.
Other quiz questions were equally meretricious. True or false - British athletes won more medals in the last Olympics than did the Germans?
Well, if you consider that the British bronze in the one-legged, red-haired, 10-metre air-rifle balloon-shooting competition is something to boast of, then bully for you.
And finally, which country has the greater foreign debt? Germany, of course.
But if one has to continually reinvest in capital equipment for the greatest export economy in the world, as well as having to integrate the industrial and social wasteland of former East Germany into the old Federal Republic, then naturally one has borrowings.
It is as if a cultural purblindness is an irremovable core of English national identity.
Presumably, that is why it needed £200m (â‚¬245m) to convince the British government that mass murder had occurred on Bloody Sunday. Otherwise, who'd have guessed?
A comparable lesson is repeated every two to four years, as a media-proclaimed English triumph is imminent in the European championships or World Cup, to be invariably followed by a grinding humiliation.
And better still - all is then completely forgotten.
This summer, the people of Britain (not just England) have every right to be proud of their resistance to the Third Reich 70 years ago.
But this shouldn't constitute a licence to concoct a history that never was.
Nonetheless, following the amnesiac ignominies of South Africa, a 1940s-based, fiction-fed fantasia is probably next on the agenda for the British media.