One of the slowest countries to lock down, Britain is now one of the worst-hit and is just starting to take tentative steps to reopen parts of the economy, aided by a newly launched track and trace system that is designed to suppress outbreaks.

But four members of Britain’s Scientific Advisory Group for Emergencies (SAGE) called the lifting premature, adding that the track and trace system was untested and unlikely to cope with an infection rate of around 8,000 new cases a day.

In response, England’s deputy chief medical officer Jonathan Van-Tam agreed that the country was at a very dangerous moment and said the easing would only work if the track and trace system succeeded, and if people followed the rules.

Van-Tam said the more than 50 members of SAGE, which includes scientists, medics and academics, often held differing opinions but they all agreed that any easing must be painstakingly slow and extremely cautious.

“This gets out of control quite quickly if you allow it to, and it then takes many weeks to get the brakes on it,” he said, adding that the track and trace system would take time to bed down and people must not “tear the pants out” of the new guidance.