The science is pretty clear about one thing – COVID-19 is spread by droplets that come out of infected people's mouths while coughing, sneezing, singing, talking and possibly just breathing.

It is also accepted by most people that wearing a face covering, or mask, cuts the chances of someone – including those who don't know they are infectious – of passing on the virus.

Many countries in the world have told people to wear face masks during the pandemic, with laws making them compulsory in enclosed public spaces such as shops and on public transport. Some countries also made them compulsory when outside the home.

But while the UK cites South Korea and others as role models for a "test, track and trace" approach to defeating the virus, it has for months rejected the other measure these countries had to stop the spread, which is the mass wearing of face masks.

In Europe, Czechia, Slovakia and Austria acted early and have a low infection and death rate, while Italy, France and Spain have all since taken similar steps and seen their infection rates fall – but the UK has remained skeptical about face coverings. Indeed, in the early stages of the pandemic using face masks was actively discouraged, with the message that they should be reserved for health workers.

Amid growing pressure, the position has been changing and the UK government has now said face coverings will be compulsory on public transport in England – although only from 15 June.

It is worth mentioning that the UK view of face masks has been fairly closely aligned with that of the World Health Organization, which says there is mixed evidence of the benefits of general wearing of face masks and says they should only be used in addition to social distancing and other protective measures, or in places where social distancing is not possible.

To find out why the UK has taken this view, we have looked through the published minutes of every meeting held about the COVID-19 pandemic by the UK's New & Emerging Respiratory Threats Advisory Group (called Nervtag in the timeline below) and the Scientific Advisory Group England (called SAGE in the timeline) committee on the advice of which the UK government says it has been basing its decisions.

We found the discussion about face masks, when there has been any, has largely been focused on the possible negative impact of recommending the use of face masks and no apparent discussion in the minutes published so far (up to 7 May) on the possible correlation between countries where face masks are worn and low transmission rates.

Here is a list of 10 reasons given for not making general face masks/coverings compulsory:

1) They might add to people's fear and anxiety

2) The evidence for mask use by anyone who is not infected "is near nil"

3) The general public might use face masks for too long ie: even if they became "soggy"

4) It could threaten supplies for healthcare workers who need them more

5) It might lead to people abandoning social distancing and hand washing

6) It might lead to people who are self-isolating leaving their home if they wear a mask

7) Inequality concerns – some might not be able to afford or be physically able to buy face masks

8) People putting a mask on and off might touch their faces more

9) Policing implications if people are wearing face masks

10) Could lead to new crimes, such as thefts of face masks

Here in more detail is a timeline of the meetings: with the references to face masks:

13 January, 2020: Nervtag holds its first COVID-19 meeting. No mention of face masks. On screening of air travelers it says: "Based on the currently available evidence, taking particular note of SARS rather than influenza and also what we currently know about the novel coronavirus, Nervtag does support the current position that port of entry screening is not advised. Nervtag is fully aware of the single case in Thailand detected by a thermal image scan but, in spite of that, the Nervtag recommendation does not change."

21 January: Nervtag meets: No mention of face masks

22 January: SAGE meets: No mention of face masks

28 January: Nervtag meets: "The existing advice in the UK (for pandemic flu) is that face mask wearing by the general public is NOT recommended." The committee was asked if this should change.

"Despite China making it mandatory in some cities for the public to wear face masks… the committee reported that there is no evidence to support that the wearing of face masks by the general public reduces transmission. It was also noted that this may add to fear and anxiety."

28 January: SAGE meets: No mention of face masks for general public

30 January: Nervtag meets: No mention of face masks

3 February: Nervtag recommends washing hands, covering nose and mouth when coughing or sneezing and the use of hand gel if there is no soap. It also says people should be asked to avoid touching their eyes, nose and mouth.

Wearing a face mask by people with COVID-19 symptoms is recommended, "if tolerated." But the wearing of face masks by well-people living with symptomatic people is not recommended, because it won't make any difference to whether they get infected. Wearing face masks by well-people interacting with well member of the public (either occupationally or otherwise) is not recommended

Members noted that the evidence for [mask] use is very weak and limited for those with prolonged contact with symptomatic individuals in the same household. The evidence for [mask] use in the general public is near nil.

3 February: SAGE meets: No mention of face masks

4 February: SAGE meets: SAGE heard that Nervtag advises that there is limited to no evidence of the benefits of the general public wearing face masks as a preventative measure. Face masks and other personal protective equipment in the community is only advised for health and social care workers visiting individuals who may be infectious. 

It says there is some evidence that wearing of face masks by symptomatic individuals may reduce transmission to other people, and therefore Nervtag also recommends that symptomatic people should be encouraged to wear a surgical face mask, providing that it can be tolerated.

6 February: SAGE meets: No mention of face masks

7 February: Nervtag: No mention of face masks

11 February: SAGE meets: No mention of face masks

13 February: SAGE meets: No mention of face masks. Instead, in the discussion about other possible measures there is a warning about 'presenteeism' – it says 20 percent of people go to work when feeling ill. It also says that any civil unrest usually relates to underlying social issues, rather than to a specific crisis; the crisis itself tends to be the flashpoint that exposes the underlying issues.

18 February: SAGE meets: No mention of face masks

20 February: SAGE meets: No mention of face masks

21 February: Nervtag: No mention of face masks for the general public

25 February: SAGE meets: Says that evidence of social distancing and school closures in Hong Kong, Wuhan and Singapore can reduce the R number to 1. Does not mention face masks.

27 February: SAGE meets: The reasonable worst case scenario was that 80 percent of UK people will be infected with 1 percent of them dying. (that's about 550,000)

3 March: SAGE meets: No mention of face masks

4 March: Nervtag: Discussion of merits of different types of personal protective equipment, but not face masks for the public

5 March: SAGE meets: No mention of face masks

6 March: Nervtag: Members raised concerns around explaining why face masks were acceptable for healthcare staff but not the general public. 

The minutes give this answer: "The difference is that healthcare staff are trained to use the masks and know when to change the masks when they become soggy or contaminated however with the general public, there is no control over how they would use the surgical face masks so they may use the same one for a week which is inappropriate."

"CS added that the surgical face masks are used by healthcare staff as part of a PPE ensemble and used alongside goggles, gloves and an apron and it is the combination of all of this that prevents contamination."

10 March: SAGE meets: Discussion of social distancing rules and reports from Italy, France, Germany and Spain on how their measures have worked. No mention of face masks.

13 March: SAGE meets: Unanimous that measures seeking to completely suppress spread of Covid19 will cause a second peak. "SAGE advises that it is a near certainty that countries such as China, where heavy suppression is under way, will experience a second peak once measures are relaxed." No mention of face masks. This is the week that saw the UK bringing in its lockdown measures.

16 March: SAGE meets: Discussion over need to shut schools, get people to self isolate and to test and social distancing. No mention of face masks.

18 March: SAGE meets: No mention of face masks. School closures need to happen, SAGE says. There is a concern that grandparents might be exposed to risk by having to take over childcare, but they hear an argument that it was most likely to impact single parents, and their parents tend to be younger, in their 50s, rather than in the more at risk age groups. Czechia made masks compulsory in supermarkets and on public transport. Slovakia followed a week later.

20 March: Nervtag: Discussion of COVID-19 aerosol route from coughing. Recommendations from the committee should have a scientific basis, but also consider the priorities for the availability of PPE in the UK, particularly with FFP3 masks.

23 March: SAGE meets: Reaffirms view that closing borders would have negligible impact on growth of cases. No mention of face masks.

26 March: SAGE meets: No mention of face masks

27 March: Nervtag: No mention of face masks. There was a discussion about nasal gargling with iodine for health care workers.

29 March: SAGE meeting: No mention of face masks (in Austria face masks are made compulsory for anyone going into a shop – its daily rate of infection drops sharply)

31 March: SAGE meeting: (R estimated at 0.6 and 0.9). No mention of face masks

2 April: SAGE meeting: No mention of face masks. This is the 22nd SAGE meeting and it includes the decision that "a future meeting of SAGE will look at what the UK can learn from actions on other countries."

7 April: SAGE meets: NERVTAG concluded that the increased use of masks would have minimal effect in stopping people becoming infected. SAGE asked for more detail on whether this view would change if it was found that pre-symptomatic people had high levels of infectiousness. The U.S. had now recommended people wear face coverings, basing the recommendation on their ability to stop people who do not know they have COVID-19 infecting other people. 

9 April: SAGE meets: Notes that the World Health Organization has said there is currently no conclusive evidence that face masks are beneficial for community use.

14 April: SAGE meets: Evidence does not currently support use of face masks to protect the wearer in the general population, although if someone is infectious it will reduce transmission. It says the evidence is marginally in favour of a small effect but only in specific circumstances - in enclosed environments. Downsides are needing to ensure people still social distance and the impact on supply chains for health workers. Agreed that a shorter paper on face masks for ministers to be presented at the next meeting.

16 April: SAGE meets: Agreement that face masks can be recommended as part of measures to release lockdown and social distancing measures but… must not threaten supplies for health staff, masks must not be allowed to lead to symptomatic people leaving their homes. Agreement for Chief Medical Officer to produce a summary of recommendations of wearing face masks.

20 April: Scientific Pandemic Influenza Group on Behaviours (SPI-B) paper on behavioural considerations of telling everyone to wear face masks: It begins with the warning "we are unaware of evidence relating to these hypotheses."

They say that "if they (face masks) are recommended the message should be that they are in addition to social distancing and should be a sign that the wearer is trying to protect other people, rather than themselves."

But the risks are: People wearing them badly, reusing them and not disposing of them properly; use of "ineffective homemade masks" because of a lack of supply of adequate ones; People may be falsely reassured by wearing face masks so do not wash their hands so much. Also raises inequality issues - those unable to afford or go outside to buy or make them; harassment of people who are not wearing face masks, which could undermine collective solidarity, and also says there are policing implications if people wear face masks.

21 April:  Sage meets: The effect of wearing face masks is weak, likely to be small but not zero. The evidence for using face masks is "marginally positive." But: Any policy decision must not jeopardise supply of masks to health and care workers. Distancing remains the preferred option but on public transport and some shops where distancing is not possible, cloth masks could be "at least partially effective." No evidence to support long term mass wearing of face coverings or wearing them outdoors. Can't rule out that those with symptoms might feel able to break quarantine by wearing a mask, others might repeatedly put a face mask on and off and that could lead to "increased hand-face contact." CMO paper to be drafted for ministers.

21 April: Scientific Pandemic Influenza Group on Behaviours (SPI-B) – warns of a risk in new crimes – including "theft of masks if designated as compulsory for public transport."

23 April: Sage meets: UK funded research project to look at how long the virus can stay on a face mask "it may survive for up to seven days."

28 April: SAGE meets: No mention of face masks

30 April: SAGE meets: No mention of face masks

1 May: SAGE meets: No mention of face masks

1 May: SAGE meets: No mention of face masks. In a media conference, after Scotland recommended people wear face masks, Prime Minister Boris Johnson says face coverings could be a useful tool in lifting the lockdown because, despite weak science, they will "give people confidence they can go back to work."

5 May: SAGE meets: No mention of face masks

7 May: SAGE meets: No mention of face masks. This is the last meeting for which the minutes have been published.

11 May: Boris Johnson announces lockdown-easing measures including advice that people in the UK wear "face coverings" – not surgical masks as they want to reserve them for health workers – in enclosed public spaces where they cannot social distance, such as on public transport and in some shops. It is not mandatory and masks are still rarely seen by shoppers and pictures are shared of people on public transport not wearing masks.

4 June: The transport secretary announces that face coverings will be mandatory on public transport in England, from 15 June. He said these face coverings should not be surgical masks but things like homemade masks or scarves. He says surgical masks must be reserved for healthcare workers and says that social distancing and hand washing remain the most important measures. There is no mention of making face masks compulsory inside shops or in any other part of daily life.

Read more: You can read the full minutes of the meetings using this link

Watch: How to make your own face mask

In-depth: The Pandemic Playbook