The use of face masks by the public, together with social distancing and handwashing, prevents the transmission of coronavirus and saves lives.

France is the latest country to do a U-turn, joining others such as the US, Austria and Singapore in advising the public to wear them. Covid-19 is spread from aerosols (tiny viral particles); we breathe in aerosols in crowded places like trains, buses and the tube, and we touch our face inadvertently numerous times with potentially infected hands. Masks will protect against this and will be even more crucial when we ease the lockdown to prevent a resurgence of cases.

The argument against mask use is incoherent. We can teach the public how to use masks properly, and ask people to use cloth masks until more medical masks are available to ensure the NHS has enough supplies.

The government has a duty to protect lives by a comprehensive strategy of social distancing, handwashing, mask-wearing and protecting the vulnerable.