After less than a week, European leaders have started to invoke parallels between the Covid-19 crisis and a state of war. The very word instinctively makes people think of the Second World War.

They may remember slogans about keeping calm and carrying on, but as the Prime Minister reminded us, we must also start to think of the possible casualty figures. He put it gently at first, saying no more than that many families would 'lose loved ones before their time'.

The scale of the threat has not even started to sink in, despite the fact that we have been given some outline figures. If both the infection rates estimated and the current death rates are true, then without intervention the numbers suggest that the casualty rate in some countries will be much greater than they suffered in the second world war.

Antony Beevor, historian, at the Cheltenham Literature Festival on October 2, 2015

A recent report from Imperial College report estimates that 81 per cent of the British population could be infected, which would be equivalent to 53.6million cases. Of these, Imperial College estimates a death rate of 0.9 per cent, so we could expect about half a million fatalities – a huge total.

Of course, all these figures are still theoretical and the different combinations of intervention through degrees of social distancing and isolation over two years should greatly reduce the final toll, but the real problem is that, as Imperial College acknowledges, 'there are very large uncertainties'.

In December 2016, the Government's then Chief Medical Officer, Sally Davies, admitted that after Exercise Cygnus, a three-day contingency planning exercise for a pandemic similar to Covid-19, they had more or less given up.

'It became clear that we could not cope with the excess bodies,' she said.

The figures on which they were working were not revealed, but how could the medical auth­orities in this or any other country dispose of more than half a million bodies, unless by mass burials in plague pits, or mass cremation?

And what would the public reaction be? Exercise Cygnus was at least prescient in warning about the critical shortage of ventilators to cope with the demand, but little appears to have been done as a result.

We have 5,000 when it is estimated that 60,000 to 100,000 might be needed at peak hospitalisation.

The epidemic of Spanish flu in 1918-19 is estimated to have infected at least 500 million people, about a third of the world's population. Estimates of death vary widely, from 17 million up to 100 million, many times more than the total of fatal casualties in the First World War itself.

It is, of course, bitterly ironic that this crisis should explode just as we approach the 75th anniversary of VE Day, for which the celebrations will also have to be cancelled. We cannot blame political leaders for using comparisons to a state of war to make populations, still reluctant to believe the scale of the threat, face the seriousness of the situation.

And yet the Second World War has become the dominant reference point for almost every crisis and conflict. In moments of turmoil, we feel we need to understand, so we look back, searching for a pattern, but history can never be a predictive mechanism.

And in this case, we are using an image of war purely as a metaphor. The enemy is not another country, which might unify us nationally, but a threat which is totally invisible and thus could prove far more divisive.

The possibility of dealing with what should be a common threat is certainly not improved by the way that traditional alliances, including the one which secured victory in the Second World War, have been rejected in many countries.

Anthony Beevor sees parallels between the coronavirus epidemic and the Second World War

This is part of a nationalist reaction against the effects of globalisation. We even have a war of words between China and the United States over responsibility for the outbreak, with Donald Trump calling Covid-19 'the Chinese virus' and the Chinese trying to blame American servicemen for introducing the infection to Wuhan.

But there has to be international co-operation if the infection is to be controlled and the world economy is to survive in any form afterwards. At this juncture, even greater questions are raised. Are we, in fact, encountering a moment of truth, a fundamental turning point in world history?

Are we facing a 'perfect storm' with medical, environmental and economic crises coming together? The extreme weather effects manifested during the past 12 months, from accelerated glacier melt, savage storms and the catastrophic fires in Australia, indicate a tipping point which cannot be ignored even when we are preoccupied by Covid-19.

Security forces order to stay home to people after state of emergency declaration as a precaution against new type of coronavirus (COVID-19) in Rabat, Morocco on March 20, 2020

To make a serious dent in reducing carbon emissions worldwide, do we need to move towards a regime of energy-rationing – almost a form of 'war socialism'? A very recent study by the University of Leeds covering 86 countries has apparently established that when it comes to transport, the richest ten per cent of the population uses 187 times more fuel than the poorest ten per cent.

Of all the flights taken by Britons, just 15 per cent of the population take 70 per cent of them. In recent years, some people have already proposed a system in which the better-off should have to purchase air miles from the poor if they wish to exceed their own ration.

And this would provide a small contribution to reducing inequality. The paradox is striking. A clear majority of voters in last year's General Election firmly rejected a form of extreme socialism, yet now faced with a combination of crises, the new Conservative Government is likely to have to consider many unpalatable measures, including large-scale nationalisation.

Crew members line up at the airport after medical experts from China arrived with medical supplies to help country's fight against coronavirus (COVID-19) outbrake in Belgrade, Serbia

History is not short of such examples. During the First World War, the Kaiser's government in Germany was forced to introduce the most extreme form of war socialism in Europe against all its reactionary instincts. It even restricted the number of pairs of boots each person could own.

Unlike those countries with the ethos of a thoroughly centralist state, we have long had a gut instinct in this country against excessive governmental controls. Most historians believe that this stretches back all the way to the 17th Century and the rule of the major-generals under Cromwell and the Protectorate.

Yet in both world wars – in 1914 with the Defence of the Realm Act, and in 1939 with the Emergency Powers Act – the vast majority of the British people did come together in support of draconian measures.

History may not be a predictive mechanism, as I say, but it does at least provide some indicators to the consequences we are likely to face in the comparatively near future. This is no time to flinch when considering them.

Members of the national police patrol the streets of Bogota, Colombia to enforce the nation's mandatory preventative isolation to control the coronavirus on March 21, 2020

It is hard to analyse the effects of the Spanish flu pandemic on pay due to the bulk of the active population serving in uniform or working in war industries during part of the period.

But to judge by the Black Death, even a relatively restricted toll would force up the cost of labour dramatically and thus trigger an inflationary spike. This would, of course, be no bad thing for the lower-paid sur­vivors who would receive large increases.

We can be reasonably sure, however, that property prices will drop, both because of the disastrous falls in stock markets, but also because the death toll will almost certainly ease the pressure on housing.

Bankruptcies, both corporate and individual, are bound to soar. Insurance companies will certainly be at risk. (No doubt only lawyers will benefit in the aftermath of allocating responsibilities.)

Perhaps worst of all, numerous studies show that the vast majority of the population has next to no financial cushion to survive even a relatively short period of unemployment.

Spanish National Police at the La Princesa Hospital in Madrid, Spain, 21 March 2020

Many European governments have made promises to help, yet there are limits to how much any government can do. Will we have to resort to a universal basic income after all?

In any case, the degree of crisis is such that the whole international economic order will be reshaped by the consequences.

A surge in criminality can also be expected. At one end of the spectrum, you might have des­perate people deciding to ignore the law, perhaps even breaking into scuba-diving shops to obtain oxygen tanks for a sick relative, all the way through to career criminals taking advantage of overwhelmed emergency services.

Scammers and thieves are already at work, going from door to door offering fake coronavirus testing as a means of gaining entry. Burglars will have a field day, knowing that even if somebody rings the police when alarms go off, nothing will happen.

The police have unfortunately advertised their limits by stating that they will respond only to lifethreatening emergencies. With so much to preoccupy us, we must also not forget the simultaneous environmental crisis of global heating.

Police at an A&E in Tbilisi, Georgia, where the country has declared a state of emergency

Its consequences will be felt locally but, above all, inter­nationally, as migration increases from regions that become uninhabitable. Europe cannot survive in anything like its present democratic form if targeted by even larger waves of migrants from Africa and the Middle East.

The threat of conflicts over water sources are increasing, while the Pacific Rim, which depends on fishing, is already facing a dearth of marine life as the oceans warm.

Those of us over 70 who are judged to be most at risk from Covid-19 must face the roulette wheel of chance with as much good grace as we can muster. But my greatest concern is for our children and their generation.

Their lives may be even more disrupted than those of my father's contemporaries in the Second World War, who lost six years of their youth. Otto von Bismarck once said cynically that the only thing we learn from history is that nobody learns from history.

But there is surely one very important lesson which we can learn from the Second World War.

The greatest threat we face would be social fragmentation in the face of existential danger. But with the right leadership, as Churchill demonstrated in the Second World War, widespread fear can be transmuted into mass courage.

Antony Beevor is the author of The Second World War, published by Weidenfeld & Nicolson.