We have never had a moment like this before in our history: a time when the Prime Minister is, in the most personal way possible, fighting the very problem his government is trying to tackle.

After Boris Johnson tested positive for coronavirus, he insisted that he would keep leading the government from self-isolation in Downing Street. His determination was influenced by the fact that No. 10 believed that parts of government needed pushing to make sure they delivered; there is frustration in Downing Street about the speed of progress in testing, for instance. But those in virtual meetings with him did worry that he was often coughing, and his performance was not up to his usual standard. When he was admitted to hospital on Sunday, some thought this would allow him to get some rest.

Even when the PM was taken to hospital, No. 10 wanted to emphasise that he was still in charge and still being sent his red box. But with the news that Johnson was to be admitted to intensive care came the announcement that Dominic Raab, the Foreign Secretary, had been asked to deputise ‘where necessary’. In all likelihood, he will need to deputise for some time. Given how hard the disease has hit Johnson, a period of convalescence would be sensible. The British political system should be mature enough to deal with this situation.

Raab is not an uncomplicated choice as deputy. There are those in the cabinet who find him abrasive, and his leadership bid last year petered out badly. But he has the title ‘First Secretary of State’ and so is the constitutional choice for the role.

One of No. 10’s worries about handing over to Raab is that he is the least well-known senior member of the cabinet. This is a disadvantage at a time when the government is trying to reassure the nation. Raab looks likely to be at the helm of government as the country reaches the peak number of deaths from coronavirus; this is expected next week. There will then be two weeks more of a considerable number of fatalities before the numbers, it is hoped, start to fall. This will be the cruellest month.

Raab is understandably keen to stress that his job is to carry out the plans that Johnson had already put in place. But on the policy question which is most preoccupy-ing ministers — what is the exit strategy from the lockdown restrictions? — there is no firm plan yet. In Downing Street, they don’t want to talk about such a plan — partly because it is believed that once people hear discussion about the end of the lockdown, they will be less likely to follow the government’s social distancing advice. This may be right, but businesses and individuals need some sense of how long these restrictions will last.

One secretary of state professes to have been shocked to learn this week that the government’s two epidemiological models both assume six months where some forms of restrictions are in place. If it is six months before the lockdown is lifted, then the economic damage caused by this virus will be immense. By the time it is ended, thousands of business will have closed for good and millions will have lost their jobs. To many ministers, six months of restrictions is unthinkable and unaffordable.

One problem for the government is that it doesn’t have all the information it needs to make decisions. For instance, it still doesn’t know what fraction of the population is likely to have had the disease. One of those intimately involved in the policy-making process laments that ‘We don’t have enough clarity to know where we are, to know what we should be doing’.

Medical answers seem a way off. A vaccine will not be available this year, the antibody tests that have been trialled so far have not worked, and even with the accelerated clinical trials for drugs such as hydroxychloroquine, it will take six to ten weeks to know whether they are effective or not. Add to this the fact that even the target of 100,000 tests a day — a figure which some in No. 10 are sceptical of the government’s ability to meet — wouldn’t be enough for a South Korean-style ‘test, track and trace’ approach, and it is clear that finding a medical way out of the crisis is going to take some time.

The debate about when to relax the lockdown is sometimes caricatured as lives vs the economy. It is, of course, a much more delicate trade-off than that. As Professor Chris Whitty, the Chief Medical Officer, has pointed out, a continued lockdown means more people could end up in poverty, which is a health risk. It is likely to result in an increase in domestic violence and mental health problems, and in a growing number of young children missing being vaccinated. And if this country ends up permanently poorer, it won’t be able to afford the same levels of health care that it currently can.

However long it does go on, the lockdown cannot be lifted in one go, because that would mean people flocking to pubs, which would boost the transmission rate of the virus. But some restrictions could be eased sooner rather than later. For example, the government was worried that its list of key workers would lead to 30 per cent of children being in school, when the aim was 20 per cent. But I understand that less than 2 per cent of children are now in school.

The rapid increase in the number of NHS beds also changes the situation. A Downing Street insider points out that ‘one of the biggest priorities was that we don’t want an Italian-style situation. We can’t have people choking to death in corridors. It is not what we want to be as a country, anything is worth it to avoid that. But once we have built up capacity to deal with it, the argument become much more nuanced’.

Another factor is how successfully other European countries end their lockdowns. In the same way that the decision by so many countries to impose restrictions led to public pressure on the UK government to do the same, if various countries manage to lift them without unleashing a second wave of the virus, that could shift public opinion. As senior government figures admit, it would be impossible to enforce a lockdown on a British public that didn’t want one.

But right now the public are anxious, and the Prime Minister is in intensive care. The debates about when to lift the lockdown will have to wait for Johnson’s recovery.