Mask-wearing “probably won’t do any good” when the government ends the legal requirement for the protection, a leading member of Sage has warned.
Graham Medley said face coverings would only work “if everybody does it”.
Boris Johnson has confirmed the lifting of England’s lockdown will go ahead on July 19.
The law requiring face masks be worn in some circumstances will be scrapped, although wearing a covering will still be encouraged.
Medley, the chairman of the Sage modelling subgroup Spi-M, told BBC Radio 4’s Today programme on Tuesday he would continue to wear a mask to protect other people.
“I think it’s quite a reasonable thing to do; it doesn’t have a huge imposition in terms of economic impact or in terms of freedom,” he said.
“There is evidence to suggest it does good, but only if everybody does it.
“So I think that, without the mandation, then we end up with a situation where even if the majority of people, let’s say 70% of people wear a mask, will that actually do any good because of the 30% who don’t? I think that is something which still needs to be determined and discussed.
“I understand the government’s reluctance to actually mandate it. On the other hand, if it’s not mandated it probably won’t do any good.”
It came as a World Health Organisation special envoy on Covid warned it was “too early to be talking about massive relaxation or freedom” despite the UK’s rollout of vaccines.
Regarding the government’s switch to personal responsibility, Dr David Nabarro told the Today programme: “What does urging caution mean? It’s important that everybody knows the best possible advice on how to prevent themselves being infected.
“I accept that vaccination has changed the nature of the equation in the UK, but quite honestly from any point of view it’s too early to be talking about massive relaxation or freedom when the outbreak curve is on such a sharp ascent.
“Yes, relax, but don’t have these mixed messages about what’s going on. This dangerous virus hasn’t gone away, its variants are coming back and are threatening those who have already been vaccinated – we have to take it seriously.”
However, chief secretary to the Treasury Stephen Barclay said there was now a need for businesses to “fire up” and it was a good time to ease restrictions.
“There’s no perfect time to do this,” he told Sky News. “What we’ve done is deploy the vaccine – an extra seven million – opening when the schools are shut is seen as the optimum time to do so.
“It’s about getting that balance right, people reaching their own judgments, being sensible, following the guidance.
“But we also need to get back to normal, businesses need to fire up, we need to get the economy going, and those are important as well because there are consequences to not doing that, both economically and in terms of people’s health.”
Modelling for Sage shows that the peak of the third wave of Covid infection across England is not expected before mid-August and could lead to 1,000 to 2,000 hospital admissions per day, with deaths at 100 to 200 per day