It need not be this way but one of the most disastrous weeks in the history of global medicine and global economics has ended with country after country retreating into their national silos. They are fighting their own individual battles against coronavirus and in their own way.

Each country has, of course, its own distinctive health systems that it relies on, rightly values its own medical experts and the disease is at a different stage in each. But why is there, as yet, no internationally coordinated medical project – equivalent to the wartime Manhattan Project – mobilising all available global resources to discover a coronavirus vaccine and to fast-track a cure?

Why, as the disease engulfs more than 100 countries, has there been no consistent, coordinated global approach not just to tracking, testing and travel but to openly learning from each other about the relative merits of quarantine and social distancing? And why, when a world recession now threatens, is there not yet an attempt at a combined effort on the part of governments and central banks to deliver a global economic response?

Instead, ours is a divided, leaderless world and we are all suffering from the tendency to go it alone: an initial cover-up in Wuhan; China’s delayed reporting to the international community; the World Health Organization (WHO) meekly agreeing that the crisis was “moderate”; and even when on 30 January it apologised and declared an international emergency, still the world continued to receive confused travel advice.

It used to be said of the Bourbons that they would never learn by their mistakes. Centuries on, national leaders still seem unable to apply or even absorb the hard-earned lesson that crises teach us, from the Sars epidemic and Ebola epidemic to the financial meltdown: that global problems need global, not just local and national, responses.

In my first days as prime minister in 2007, the Labour government had to grapple, in quick succession, with an international terrorist incident, floods, a foot and mouth outbreak, avian flu and the first banking crash of the global financial crisis. “There are decades when nothing happens,” Lenin wrote, “And there are weeks when decades happen.” This succession of challenges taught me that governments will rapidly lose control of events unless they immediately pull out all the stops to get to the root of the problem, and then move with decisive and overwhelming force and resolve.

In October 2008, within days of the Lehman Brothers collapse, bankrupt banks, which had been running capitalism without capital, were nationalised and recapitalised. The lesson for today is as stark: you can cut interest rates and payroll taxes and focus your energies on dealing with the after-effects. But you will not succeed unless you can also build confidence that you have a clear-cut medical response to what is a global health emergency .

‘Our willingness to cooperate is becoming inversely related to our need to do so.’ A woman wearing a protective face mask walks in front of the Bank of England Photograph: Henry Nicholls/Reuters

But the global financial crisis also taught me that while you need the analysis and advice of expert organisations such as the International Monetary Fund (IMF) and now the WHO, you also need political leaders in every continent with the courage not just to lead but to work together. And the best way to do so is in a global forum – in 2008, this was the G20 leaders’ group – within which decisions can be agreed. These decisions will then carry authority and legitimacy.

But what depth of dialogue has there been today between the main global players – Presidents Xi, Trump, Moon of South Korea, and Prime Minister Conte of Italy – to benefit from each other’s insights on travel restrictions, lockdowns and social distancing? Take testing: while the UK is way ahead of Trump’s America, Britain had, up to 10 March, tested at less than half the rate of Italy and a just over a 10th the rate of South Korea. Slow to test patients who had not been in China, Italy or South Korea, perhaps we had something to learn from China’s decision to test even the most marginal cases? And the delays in testing sum up why fears are still growing for our safety: despite the brilliance of Britain’s medics, the government still seems behind the coronavirus curve.

Of course, the very idea of global collaboration – and the convening of what would be a “virtual” G20 – sits uneasily with the “America first”, “China first”, “India first” and “Russia first” populist nationalism that has been subdividing our world. Since the high point of cooperation in 2009, nationalists have been in the ascendant – building walls, closing borders, clamping down on immigrants and imposing tariffs. And what was first a protectionist nationalism has morphed into an aggressive us-versus-them unilateralism.

Our willingness to cooperate is becoming inversely related to our need to do so, and this insularity means we are fighting today’s pandemic with under-resourced international institutions, not least a WHO to which ever more responsibilities have been added without the financial means to discharge them. In fact, despite a number of laudable post-Ebola initiatives – including the new vaccine fund (Cepi) – we are $9bn short of the funding needed for medical R&D and contingency planning. Sadly leaders either panic, as now – or, until disaster hits, follow the course of least resistance: inattention and neglect.

What’s more, this us-versus-them nationalism has spawned a blame culture, with under-pressure governments holding everyone but themselves responsible for anything that goes wrong. And yet an ideology of “everyone for himself” will not work when the health of each of us depends so unavoidably on the health of all of us.

‘An ideology of ‘everyone for himself’ will not work when the health of each of us depends so unavoidably on the health of all of us.’ An elderly man walks down a deserted street in Venice Photograph: Manuel Silvestri/Reuters

In the financial crisis, governments did come together – with globally coordinated interest rate cuts, fiscal stimuli, currency swaps and anti-protectionist deals. A decade on, rising nationalism will likely block central bank cooperation and an early easing of trade restrictions. Today, also, interest rates are currently so low that there is far less scope for monetary activism. The world’s central banks – for the last 10 years just about the only game in town – are increasingly exposed as emperors with few clothes.

I believe a concerted global, governmental response is still possible. Each country should commit to removing blockages in supply chains; be ready to ease tariffs (and certainly not add to them, as rushing at the Brexit deadline might do); extend credit, as the UK has rightly announced to businesses, including a moratorium on tax payments; and guarantee upfront financial support for workers sent home or on short time. And where countries cannot afford to do so, the IMF and World Bank should be asked, as in 2009, to step up.

But the economic shock we face today – a ruptured international supply chain and, soon, millions able to work only from home – demands innovative thinking that is more in tune with our digital age. An industrial policy, backed up by fiscal firepower, could accelerate the workplace revolution that is already under way: from making business decisions via teleconferencing to the provision of online education, health and other services. Thus allowing millions to continue to work, study, organise their lives and make a living from home.

Yet no individual initiative will substitute for a collective declaration that, working together, the world’s governments will do whatever it takes. Coronavirus will not be the last, nor the worst, pandemic. But if the Manhattan Project could bring people together in the 1940s to create the most lethal weapon in human history, surely we can come together, in the 21st century, to save both lives and the livelihood of millions. We may not be able to repeat Roosevelt’s New Deal-era promise that there is nothing to fear but fear itself, but confidence in the future can be regained only by bold international actions that build confidence today.

• Gordon Brown was UK prime minister from 2007 to 2010