The president of the Royal Society has said everyone should wear a face covering in public to help tackle the Covid-19 outbreak.

Professor Venki Ramakrishnan called for people to be required to wear a face covering when they leave their homes, particularly in enclosed indoor spaces.

Here is what you need to know about the current guidance on wearing masks and coverings:

– What is a face covering?

Face coverings are not the same as face masks. The Government has stated that coverings can be made from scarves, bandanas or other fabric items, as long as they cover the mouth and nose.

They should allow the wearer to breathe comfortably and be tied behind the head to provide a “snug fit”.

– What about face masks?

People have been asked not to use medical-grade personal protective equipment (PPE) masks to ensure these remain available for frontline healthcare workers.

– When am I required to wear a face covering?

They are mandatory on public transport in England, although exemptions include young children, disabled people and those with breathing difficulties.

All hospital visitors and outpatients in England must wear face coverings, while all hospital staff are required to wear surgical masks.

Official guidance says those in England should also wear a face covering in enclosed public spaces where social distancing is not possible.

– What are the rules for the rest of the UK?

In Scotland, face coverings are required on public transport, and it will be compulsory to wear them in shops from July 10.

Face coverings are advised in Wales in situations “where social distancing is not possible” – but have not been made mandatory.

Meanwhile, from July 10, they will be compulsory when travelling on public transport in Northern Ireland.

– Why are face coverings being recommended?

The Government states that, while wearing a face covering does not protect the wearer, it may protect others if people are infected but have not yet developed symptoms.

– If I develop Covid-19 symptoms, can I still go out if I wear a mask or covering?

No. People with symptoms and their household should isolate at home.

– What is the science?

The Scientific Advisory Group for Emergencies (Sage) says evidence does not currently support the use of face masks to protect the wearer in the general population, although if someone is infectious with symptoms, they will reduce transmission.

The group found the evidence is marginally in favour of a small effect, but only in enclosed environments.

– What has the World Health Organisation said?

The WHO has concluded that the use of a medical mask could prevent the spread of droplets from an infected person.

It said, however, there is no evidence that wearing a mask – whether medical or other types – by healthy people in the wider community can protect them from infection with respiratory viruses, including Covid-19.

– Are there any downsides to using face coverings?

Sage says that some risks of transmission exist by people wearing masks, including people by putting them on incorrectly, touching their face more than normal while wearing one, reusing them, and not disposing of them properly.

People may be falsely reassured by wearing masks so do not wash their hands so much and may use “ineffective homemade masks”, the group adds.