OK so weak and small:
Professor Dame Angela McLean, the UK deputy chief scientific adviser, confirmed that Sage recommended that there was “weak evidence of a small effect in which a face mask can prevent a source of infection going from somebody who is infected to the people around them”.
McLean said: “Under our current circumstances, anybody who has symptoms really must stay at home ... but we are also concerned that some people are infected who don’t have symptoms, or maybe don’t have symptoms yet, and that is the reason that Sage has put so much effort into looking at this question,” she said.
“But the answer is clear that the evidence is weak and the effect is small, and we have passed that on to our colleagues in government with which to make a decision.”
But given the current toll, even a very small effect could make a worthwhile difference. Let us suggest that they could prevent just one person a day from going down with covid-19, that is worth a lot to that person and their family. Especially if the person doesn't then die from it.
The only thing that would make me agree with continuing not to recommend masks is evidence that they do actually worsen the situation.
And they still keep repeating about people with symptoms:
One government source said there was still clear concern among some ministers about changing the UK advice at this stage, when people with symptoms are being advised to stay at home anyway.
Are they entirely without brains? The issue is very largely people who are symptomless.
I belong to that group of people who believe that "follow the science" (or however they wish to put it) mandates changing advice if the science shows the need. Not changing it is absolutely wrong.