In science as in politics, the first step to understanding a mistake is to acknowledge it. Scientists, though not universally, are often better at doing this than politicians. Hence the admission by Sir Patrick Vallance, chief scientific adviser to the government, that early British success in testing during the coronavirus pandemic was not “scaled up” rapidly enough at a critical moment in the spread of Covid-19.

It follows the admission last week from his colleague Chris Whitty that Germany “got ahead” in testing people for the disease. This was in the period when the advice of the World Health Organisation to “test, test, test” was dismissed by Mr Whitty’s deputy, Jenny Harries, because Britain already had a well-developed public health system.