Senior doctors are pleading with the public to help prevent a second wave of coronavirus that could “devastate” the NHS, amid concern at mixed government messages about face masks and returning to work.

Prof Carrie MacEwen, chair of the Academy of Medical Royal Colleges, said medics and healthcare workers felt “totally reliant on the public understanding that this has certainly not disappeared and could come back and cause even more suffering for the population.”

Dr Alison Pittard, head of the Faculty of Intensive Care Medicine, also warned the NHS could be “overwhelmed” by a second wave coinciding with seasonal flu and the consequences of the backlog of treatment for serious illnesses including cancer.

“People might think Covid is over with, why do I have to wear a face mask,” she said. “But it isn’t over. We still have Covid patients in intensive care. If the public don’t physically distance and don’t wear face coverings we could very quickly get back to where we were earlier this year.”

Downing Street has said its scientific advice is that new infections are falling at a rate between 1% and 5% a day across the UK. But on Sunday, the Scottish government confirmed a rise in new cases for the fifth consecutive day with 23 people testing positive – the highest daily rate since 21 June. Meanwhile in Blackburn and Darwen, where health officials last week ordered new restrictions to reduce virus spread, Dominic Harrison, the director of public health, has said the national tracing system was only managing to reach half of those who had been in close contact with a coronavirus patient.

The British Medical Association said a second peak, combined with a seasonal flu outbreak, could be “devastating for the NHS” and voiced criticism of government guidance on the use of face coverings.

Masks will be compulsory in shops in England from this Friday, with a £100 fine for those who flout the law. But they are not being required in offices.

The health secretary, Matt Hancock, has said: “When you’re in close proximity with somebody that you have to work closely to, if you’re there for a long time with them, then a mask doesn’t offer that protection.”