On face coverings, Johnson again seems to be following rather than leading

In the curious form of devolution that the UK has adopted, Nicola Sturgeon sometimes gets to announce things before Boris Johnson, although usually it is the other way round. On the question of requiring people to wear masks in shops, Ms Sturgeon made the announcement 10 days ago that it would be compulsory in Scotland from Friday.

Mr Johnson seems to be proceeding more tentatively in the same direction. During Friday’s “People’s PMQs”, in which the prime minister answered questions from members of the public, he said: “We are looking at ways of making sure that people really do have face coverings in shops.”

Shortly afterwards, he was photographed in a shop and a cafe in his Uxbridge constituency, wearing a Tory blue mask. And a government “source” was quoted as saying it was a “fair assumption” that masks would become mandatory in shops and other indoor public places “within a few weeks”.

This is an unsatisfactory way of making policy. Either the government judges that masks are likely to be useful in controlling the virus, or it does not. If it does, and it makes the further judgement that compulsion is needed to secure an effective level of compliance, then why wait?

Even if the prime minister’s view is that the evidence is ambiguous but that widespread mask-wearing is a way to instil confidence that it is safe to go shopping, he should take a decision and stick to it. This game of grandmother’s footsteps is instead undermining confidence in the government’s policy.

In fact, the government does have a position, reflected in the most recent guidance, which is that people should wear a face covering, if possible, in enclosed public spaces where keeping two metres away from strangers is not possible. Yet so far the only compulsory part of that policy in England is on public transport – although anyone who has been on a bus or train in the past few days will have noticed a fairly low level of compliance.

And the prime minister seemed to undermine the government view somewhat by saying on Friday that washing hands was “much more important” than face coverings. We suspect that the evidence on this is unclear. He also said: “The balance of scientific opinion seems to have shifted more in favour of them than it

was, and we’re very keen to follow that.” But that balance shifted – among the members of the Scientific Advisory Group for Emergencies in this country – weeks and weeks ago.

We do not know whether Mr Johnson’s instinctive liberalism is holding him back, as it did in the early stages of the epidemic. The Independent is all for liberalism, and an instinctive belief in the right of citizens to make their own decisions about their health, but an infectious disease imposes obligations as well as rights, given that an individual’s actions may have dramatic negative consequences for the wellbeing of others.

In such a situation, an element of temporary compulsion is justified. The government already has a policy, which is that face coverings should be worn indoors where two-metre distancing is not possible. It is not possible in almost all shops and indoor venues, and therefore face coverings should be required as a condition of admission. The prime minister should have announced this long ago; failing that, he should do so without further delay.