Why the government has changed course on face coverings?

The key word explaining the government’s U-turn on face coverings is “asymptomatic".

That’s when people are infected with the virus but don’t realise it because they don’t show any symptoms.

Or when they’ve caught the virus but haven’t yet noticed because the coughing and fever haven’t started.

In both cases, people can be spreading the virus unawares, and that could prove dangerous in crowded places.

That’s why a month ago the US government, followed by many others including the Scottish government, decided to advise people to cover their faces.

This isn’t designed to protect the wearer – a homemade mask will not be very effective at that.

Instead a covering made from a scarf or T-shirt is meant to trap any virus that you might otherwise be transmitting to people nearby.

In many countries, wearing a mask has become an act of solidarity, an effort to protect others from the disease.