Britons are now being asked to cover their face when in enclosed spaces where social distancing is not possible, such as in shops or on public transport, the Government has said in a new document.
The advice applies to people in England, Scotland, and Northern Ireland.
It said face coverings were intended to protect against inadvertent transmission of coronavirus to others if the wearer has it asymptomatically, rather than to protect the wearer.
The Government also differentiated between face masks and face coverings. The former includes surgical masks, respirators and other forms of personal protective equipment, which should be reserved for healthcare staff and other key workers who need them.
People should buy other face coverings or make their own, the guidance said.
Shoppers who have already attempted to buy protective gear online have reported receiving poorly-made masks that do not fulfill safety requirements or being charged extortionate amounts. Follow our guide on how not to get ripped off.
Should I wear a face mask?
Britons have been told to wear a face covering when they will be in contact with people outside of their household in a confined space.
Children under the age of two do not need to cover their faces, nor do those who may struggle to wear one correctly for example young children or those with respiratory conditions. Wearers must ensure they use coverings correctly and wash their hands before putting them on and removing them, the guidance states.
People can buy face masks, so long as they are not surgical masks intended for hospitals and care workers, or make a face covering themselves.
Read more: How to make your own face mask
What level of protection do I need?
The most protective types of masks are FFP2, FFP3 or N95 respirators, followed by medical-grade surgical masks, however these are only to be used by those working in close contact with Covid-19 patients.
If you do choose to wear a mask make sure it fits snugly around your mouth, nose and chin and can filter out particles that could be contaminated.