As a young journalist working in London between the two world wars, the Italian writer Luigi Barzini sought an explanation as to how a damp and peripheral island in the North Sea should have risen from primitive squalor to world domination. What was the British secret? Were they supermen? He dined out in London clubland, interviewed ministers, drank with Fleet Street journalists, attended parliamentary debates and visited the British Museum in pursuit of an answer.

Military and naval supremacy, technical proficiency, wealth and the possession of colonies did not provide an explanation, he decided; these were the result of greatness, not its cause. Nor was it the case that the British were necessarily more intelligent than others, although he was amused to discover that because the typical English gentleman went to great lengths to conceal his intelligence it was impossible for a foreigner to know whether he was intelligent or stupid.

Italians, like most Mediterranean peoples, tended to assume that a nimble mind, quick reflexes, eloquence and improvisation were the key to success. Many Italians continued to believe this even though such cleverness had repeatedly led their country to catastrophe. The British harboured no such illusions.

After diligent research and much reflection Barzini concluded that the answer was to be found in the moral character of the people. Stoicism and imperturbability were important features of that character, but the key factor was the ability of the English to act as one in times of danger, irrespective of birth, class and rank. At such times even dullards behaved with intelligence. “I discovered that some of them [the English] were definitely intelligent and that a few were exceptionally so, more than the average Continental, but that it was practically impossible to separate the dull from the acute, the Sherlock Holmeses from the Dr Watsons … [in a crisis] they all behaved and spoke alike. On the other hand, all of them, the dull and the acute, somehow knew how to act bravely, splendidly and usually successfully in critical or difficult circumstances as if they had all been intelligent and that this capacity of theirs was the secret that made their country great.”

It is clear from the plight of many other countries that the British response to the crisis is not universal

According to Barzini (who was never tempted to emulate the understatement of those he observed) this trait explained why in bygone days, when faced with a crisis in distant lands with no possibility of communicating with superiors, weeks or months away from London by sailing ship, admirals, generals, governors, ambassadors or young administrators alone in their immense districts had always known what to do. They acted in a way that the prime minister, the monarch, the Archbishop of Canterbury and the editor of The Times would have approved of because they would have acted in the same way.

No one, Barzini pointed out, had told Kitchener what to do at the time of the Fashoda incident when British forces thwarted a French attempt to gain control of the Upper Nile. Kitchener knew immediately what had to be done in the national interest and the authorities in London extended their blind trust in him because they knew that this would be the case. This trait was not the preserve of the ruling class, he later explained. It was famously evident at Dunkirk and during the Falklands crisis, occasions on which ancient British virtues, often written off, shone again.

National character is not immutable or unchanging. Socialism, economic change, immigration and the loss of empire have all left a mark. These days politicians seldom display the degree of imperturbability that so impressed Barzini, although Sir Patrick Vallance, Britain’s chief scientific adviser and Professor Chris Whitty, England’s chief medical officer, the two men on whom we crucially depend in the battle to contain the coronavirus pandemic, appear to be very models of it.

Likewise, the stoicism celebrated by Kipling, and reflected in popular culture (for example, Harry Lauder’s First World War song “Keep Right on to the End of the Road”) is no longer as prominent as formerly, although not yet extinct. But the instinct to pull together at moments of acute danger remains.

It is certainly evident now. It can be seen in the willingness of 750,000 British people to volunteer to deliver food to the elderly, to assist doctors and to make phone contact with the lonely and isolated. It is evident in the willingness of retired doctors and policemen to return to duty, in the offer of cab drivers to give lifts to nurses, in the collaboration between University College London and British firms to produce ventilators at breakneck speed, in the flow of charitable donations to those hit hardest by those whose incomes and savings must inevitably taken a hit, as well as in millions of individual acts of kindness, most notably Captain Tom Moore, aged 99, raising  more than £25 million for the NHS by walking with his Zimmer frame round his Bedfordshire garden. A recent survey shows that people feel less lonely and isolated than before the pandemic took hold. And as I write, my wife, along with other members of her quilting club, is making cotton bags in which nurses can store a change of uniform.

For the British there is nothing extraordinary in any of this; it is scarcely a matter of comment. It is how we normally behave when things get tough. But it is clear from the plight of many other countries that the British response to the crisis is not universal. Those who have worked for an extended period abroad or who, like the Telegraph’s Janet Daley were born and brought up elsewhere, are apt to display a greater appreciation of this national characteristic. She wrote: “Just a matter of weeks ago the nation was divided into two tribes who apparently loathed one another: families were divided, old friendships were abandoned and workplaces poisoned by mutual antagonism. Well, that was then . . . ”

It is not just that old friendships have been repaired, with neighbours offering constant contact and greater support than has been witnessed for decades but, she noted, that people have come up with ingenious and creative solutions to an unexpected dilemma and done so far more quickly than government agencies. As the Queen observed in her address to the nation, “The attributes of self-discipline, of quiet good-humoured resolve and of fellow feeling still characterise this country.”

Left-wingers feel uncomfortable about talk of national traits, whose existence they are apt to deny. Interviewed on the Today programme, Polly Toynbee suggested that the prevailing sense of unity was pretty much matched by sentiment and conduct elsewhere. She is mistaken. In Spain, the antagonism resulting from the doomed bid for Catalan independence has often been compared to the divisions caused by Brexit. But the former has been exacerbated, not diminished, by the pandemic, as the government in Barcelona blames Madrid for alleged incompetence.

Marines have joined the Guardia Civil in Spanish street patrols, handing out 144,000 fines during a 12-day period. The public mood has been one of resentment and anger. In Italy, there are reports of impending social unrest, while politicians blame one another and predict that the EU will implode unless agreement is reached on plans to create “corona bonds” to help southern Europeans.

In the US Congress cross-party agreement was finally agreed on a huge financial package to prevent economic collapse, but it can hardly be said that the pandemic has led to a healing of the divisions caused by the country’s ongoing culture wars. Only in Britain has support for government measures remained robust.

Such has been the strength of national mood that when high-profile individuals such as Mike Ashley, the head of Sports Direct, and Tim Martin, the rough-hewn Brexiteer boss of JD Wetherspoon, appeared to put their own selfish interests before that of the general good, both felt it necessary to backtrack. (Ashley also sought to make amends by placing his company’s delivery vehicles at the disposal of the NHS.)

In its struggle to contain Covid-19 the UK government consequently possesses a tremendous asset shared with few others. It could fracture through major ministerial incompetence, lies or bad leadership, none of which are presently evident. One outcome may be greater awareness of the structural weaknesses of an overly centralised and bureaucratic system based on the impossible dream of providing universal healthcare free at the point of supply. But that will come later and will not impinge on the present mood of unity.

Following the announcement of the lockdown and the chancellor’s measures to protect jobs and incomes, support for Boris Johnson reached 67 per cent, a higher level than for any leader of recent memory and without equal in Europe. It is unlikely to remain at this level, but at the time of writing there is no sign whatever of a collapse of public support or of any indication that majority opinion favours a rush to judgment; it is understood that this must come later.

If when the pandemic comes to an end, Britain emerges with its institutions intact and, despite the immense economic damage caused, a general expectation of better days to come, this will be due in large part to the national traits which Barzini described in his entertaining description of the British character. As the Queen stressed, that success will belong to all of us. We should not make too much of this. It would be unBritish to do so.