Boris Johnson has urged the public to wear face coverings in shops, and said an announcement on whether their use will be compulsory in England will be made in the coming days.

The Prime Minister said that ministers are considering what “tools of enforcement” could be employed as he described the evidence to support their use to slow the spread of coronavirus as “growing”.

Downing Street said on Monday that a formal review was under way after the Government faced calls for clarity on the subject.

But Labour called on the Government to address the “confusion” around the use of non-surgical masks “without delay”.

Stricter measures for shoppers in England could bring the nation into line with Scotland, where First Minister Nicola Sturgeon made their use compulsory in shops as of Friday.

The PM, wearing a covering during a visit to the London Ambulance Service, said they “have a great deal of value in confined spaces” where people are coming into contact with those they do not normally meet.

He said: “Yes face coverings, I think people should be wearing in shops and in terms of how we do that, whether we will be making that mandatory or not we will be looking at the guidance, we will be saying a little bit more in the next few days.

“We will be looking in the next few days about exactly how, with what tools of enforcement, we think we want to make progress.

“As the virus comes down in incidence and we have more and more success, I think face coverings are a kind of extra insurance we can all use to stop it coming back and stop it getting out of control again.”

After the PM’s interview, Labour wrote to Health Secretary Matt Hancock calling for him to urgently address the issue amid mixed messages from the Westminster Government.

Cabinet Office minister Michael Gove had said on Sunday it was “best to trust people’s common sense” rather than force them to adopt coverings despite the PM earlier saying he would support “stricter” measures.

Shadow health secretary Jonathan Ashworth wrote: “Conflicting advice and conflicting statements from the Government only hinder our fight against the virus. Clear communication is vital in combating the spread of Covid-19.

“For the public to know that they are doing the right thing in shops, restaurants and other crowded places, I am asking that you urgently set out the position on face coverings.

“As lockdown rules are further relaxed this week, it is vital that updated guidance on this issue is published by the Government without delay.”

Justice Secretary Robert Buckland also suggested he could support the use of face coverings being made compulsory as an expert advising the Government as part of the Scientific Advisory Group for Emergencies (Sage) acknowledged the evidence has “shifted”.

Royal Society president Dr Venki Ramakrishnan told ITV’s Good Morning Britain: “It’s now quite strongly in favour of using face coverings in enclosed spaces where we’re likely to come into contact with strangers.

“I think that the Government should be very clear. It’s not consistent to make it mandatory on public transport and not make it mandatory in other enclosed and busy public spaces, because the behaviour of the virus is the same in all of these spaces.”

An alternative group of scientists calling itself Independent Sage urged the Government to quickly legislate to include the mandatory wearing of face coverings in public spaces with limited ventilation, including shops.

It believes some studies “strongly suggest” mandatory use “can substantially reduce infection rates”.

The Usdaw union representing shop workers joined the calls for the Government to set out its position, saying the early signs are that the measure has been “working well” in Scotland.

General secretary Paddy Lillis said: “We welcome anything that helps to keep customers and shop workers safe, but the most important measures to help stop the spread of Covid-19 are to maintain proper social distancing and hygiene.

“We need clarity from the Government, the mixed messaging and indecision is not helpful for shop workers.”

Meanwhile, Wales’s First Minister Mark Drakeford said the nation would be brought into line with England and Scotland when face coverings are made compulsory on public transport in Wales from July 27.

And Mr Johnson urged the public to consider returning to workplaces as the lockdown further eased in England on Monday with the reopening of beauty salons, nail bars and tattoo parlours.

The PM said: “Where businesses have made a huge effort to make the workplace safe, I do think people should start to think about getting back to work but provided we all continue to follow the precautions.”

The work-from-home guidance currently in place was under review, No 10 added.