Leadership matters in a crisis. In a huge crisis, therefore, leadership ought to matter even more than ever. Britain, with its potent memories of war leadership, is particularly predisposed to this view. Today, along with the rest of the world, the country faces an exceptional public health crisis in the shape of the Covid-19 pandemic. But it is not alone in finding that the leadership being offered in the current crisis is far from exceptional.

Britain’s current failures of leadership are not now a matter of opinion but of fact. Hopefully they will not prove catastrophic, but they need to be recognised and avoided in future as far as humanly possible. The understandable instinct to rally round, to do our bit, to defer to authority and to postpone difficult subjects until afterwards all contribute to a widely shared wish to make the best of things in difficult times. This is naturally much enhanced by Boris Johnson’s personal struggle in intensive care, again wholly understandably so. But these could yet be dangerous responses.

A powerful report by Stephen Grey and Andrew MacAskill for Reuters this week is the latest of many pieces of good reporting to illuminate some of the key failings. Importantly, these failings are shared between politicians, officials and advisers. The key one is that Britain’s senior scientific advisers knew, by late February, that the country faced the possibility of half a million deaths from Covid-19 and was ill-equipped to prevent that outcome. But, for a variety of reasons, they failed to make the case strongly enough to ministers.

Political leaders were slow and reluctant to accept such a dire warning. But, just as crucially, the scientists and officials were slow and reluctant to press their view in the face of politicians’ reluctance. As a result, political leaders and experts succumbed to the equally natural temptation to put the best face on things, and not to create fear. Meanwhile, the rest of us mainly went on with life as usual, even though there was growing evidence of the scale of the threat.

Britain, along with many others, was unprepared. Part of this – but certainly not the entire problem – is a failure of leadership. Every country has had its leadership failures in this pandemic. Those in the United States have been significantly worse. Two weeks ago, a US official told the Washington Post in words echoing the official report into intelligence failings before 9/11 that “the system was blinking red” with warnings about the likely pandemic. They were ignored by Donald Trump and his team.

The conclusion from this should not be that all leaders are useless or equally open to criticism. Most leaders are better at their jobs than Trump. Leadership is difficult. But there is a difference between better leadership and worse leadership, and it is not unreasonable for leaders to try to do their best to lead well.

Business leaders are often – but not invariably, as Trump proves – better at this than politicians. They learn to incant rules like “Don’t say things will not change”, “Never promise more than you can deliver” and “Don’t stretch the truth”. They may then forget those rules, especially in difficult times, but at least the rules nag away at them, and at least their staff are in a position to remind them to stick to them.

All three of those rules have been stress-tested in the British political response to the pandemic. Johnson’s reluctance to impose a lockdown earlier than he did illustrates his deep instinct for telling people things will not change, and they can have their cake and eat it. The insistence of the health secretary, Matt Hancock, that the UK will test 100,000 people for coronavirus symptoms and antibodies by the end of this month looks set to be a classic instance of promising more than can reliably be delivered. Jeremy Corbyn’s claim that the pandemic “vindicated” the economic policies he promoted as Labour leader was a mischievous stretching of the truth that provoked only derision.

Too many political leaders think they can trust to their own example in trying to lead. That was as true of Margaret Thatcher as it was true of Tony Blair or Gordon Brown. It was also true today of Johnson, before he was stricken. Modern politics undervalues technocratic skills. But it does this at its peril, as the Reuters account shows. It is striking that the British minister whose reputation is still advancing in the crisis is the chancellor Rishi Sunak, who is a quintessential technocrat.

How can British politicians be better leaders in critical times? Here are three suggestions. The first arises directly out of the reported diffidence and avoidance of awkward argument that the Reuters account describes. Leaders should not surround themselves with courtiers, as Johnson has done. Government needs rational policymaking. It needs people who can play devil’s advocate and make a reasoned case for an alternative. Prime ministers should create decision-making structures in which awkward realities are not brushed under the carpet or fudged.

Second, leaders should admit from the outset that they may get things wrong. One of the many greatnesses of Franklin Roosevelt was that, right from the start of his presidency, he admitted there would be failures along the way. Roosevelt’s ability to convince Americans that he would rebuild the country after the Depression meant that he was also able to say that if he got something wrong, he would try another solution instead, and they should still trust him. Lesser politicians are often paralysed by the terror of admitting failure. Roosevelt showed how a great leader can give themselves elbow room to make mistakes and still retain credibility.

Third, leaders should never believe they have preternatural political abilities. Recent prime ministers from Blair to David Cameron have succumbed to this delusion in various ways. But not even Churchill had it all. His flaws were immense, and needed to be reined in. As Conservative prime minister, Stanley Baldwin – who was certainly flawed too – once said: “When Winston was born lots of fairies swooped down on his cradle with gifts – imagination, eloquence, industry, ability; and then came a fairy who said, ‘No one person has a right to so many gifts,’ picked him up and gave him such a shake and twist that with all these gifts he was denied judgment and wisdom.”

Exceptional times call for exceptional leaders. But in this exceptional crisis Britain does not necessarily need leaders with the skills of the past: the audacity of Churchill, the steeliness of Thatcher, the persuasiveness of Blair or the obsessiveness of Brown. It needs leaders who are practical about difficult and ambitious policy aims, open with the public about what will have to change, and who convey the kind of awareness and reliability that allows voters to trust them. In spite of the many myths that surround it, good leadership still matters a lot. And in this pandemic crisis, it could make a life-and-death difference.

• Martin Kettle is a Guardian columnist