Business Secretary Kwasi Kwarteng said he believed in “individual responsibility” but he would continue to wear a mask on the Tube after mask rules are ditched in England on July 19.
It puts him at odds with Communities Secretary Robert Jenrick who said on Sunday he would not be wearing a mask after it is no longer mandatory.
It also comes amid a growing row with the Mayor of London Sadiq Khan who has urged the government to retain the requirement for coverings on public transport. Greater Manchester Mayor Andy Burnham agreed saying the change could cause “real problems”.
Mr Kwarteng told Sky News: “I’ve always said that I believe in individual responsibility. I think businesses have their own discretion – their own judgement.
“Personally, I use the Tube a lot in London and I would probably use them – wear a mask – in that context in the Tube in public transport. That’s a personal view. It’s not something that I would mandate or necessarily dictate to other people.”
He said he was happy for businesses to continue to require face masks on their premises, saying it was their “discretion”.
Adding to the confusion, Transport Secretary Grant Shapps said he would be “very relaxed” if the London mayor mandated the use of masks on public transport in the capital from July 19.
He told MPs: “On a crowded Underground train it may feel right to wear a face covering for the next period.”
It is understood there would be a number of practical implications if the London transport system was to make masks mandatory – including all the different train operators.
Mr Johnson has said face masks will be a matter of “personal responsibility” after July, but some companies have said they will continue to ask people to wear coverings.
Ryanair and easyJet have said face masks will remain compulsory on their flights even once the nationwide mandate lifts.
Sir Paul Nurse, chief executive of the Crick Institute and patron of Scientists for Labour, said: “It makes no sense to me at all not to insist on face coverings even masks in crowded situations like commuting railways and buses during the rush hour.”
Dr Jeff Barrett, director of the Covid-19 genomics initiative at the Wellcome Sanger Institute, said a “big risk” of the Government’s strategy was “very high” case numbers of 100,000s a day.
He told BBC Radio 4’s Today programme that vaccines lessen the risk of the disease but added: “Nothing about that changes this risk of the virus mutating and obviously the thing which now would be really worrying is if and we don’t know how likely this is but if a mutation that substantially reduced the efficacy of the vaccines happened.”
Meanwhile, the World Health Organisation still advises masks continuing to be mandatory on public transport, in shops and in crowded places.
Unite union has said that dropping mask-wearing on public transport would be “gross negligence”.
Professor Laurence Lovat, clinical director at WEISS Centre at UCL, questioned the decision, saying masks were a “really simple way” to prevent people from transmitting disease to others.
Dr Katherine Henderson, president of the Royal College of Emergency Medicine, said that face masks may still be needed in A&E departments to “keep people safe”.
She told Times Radio: “A&E departments are often quite crowded environments and that’s one of our worries – so as people come in we may need mask-wearing to help keep other people safe because you might be an asymptomatic carrier and come with a cut finger, but you might be near somebody who’s immunosuppressed with a kidney transplant.”
Asked where and when he would continue to wear a mask, Mr Johnson told a Downing Street press conference: “It will depend on the circumstances. Clearly there’s a big difference between travelling on a crowded Tube train and sitting late at night in a virtually empty carriage on the main railway line.
“We want people to exercise their personal responsibility but remember the value of face coverings both in protecting themselves and others.”