Winter will be “tricky” with the double threat of Covid-19 and a resurgence of other respiratory viruses which were kept at bay during lockdowns, England’s chief medical officer has warned.

Professor Chris Whitty said the situation could be “very difficult” for the health service as a result.

Both he and Boris Johnson said it is better to lift restrictions now rather than delay until autumn or winter, when the Prime Minister said the virus would have “an edge”.

Prof Whitty said he is of the “strong view” that a summer reopening “has some advantages” over autumn, when schools return, and winter “when the NHS tends to be under greatest pressure for many other reasons”.

He told a Downing Street press conference: “The winter is inevitably going to be tricky and this winter the NHS is likely to have both Covid and some resurgence of other respiratory viruses that were suppressed by the degree of lockdown last time round.

“So I think we should be realistic and this coming winter may be very difficult for the NHS.”

Mr Johnson stressed that a final decision on the July 19 reopening will not be taken until next week, and NHS Providers – which represents trusts – urged him to “keep a very close watch” on the data in the days ahead.

Saffron Cordery, deputy chief executive of the organisation, said trust leaders expect decisions “to be driven by data, not a date”.

She added: “The Prime Minister acknowledged the inevitability of increased Covid-19 infections, admissions to hospital and deaths in the coming weeks.

“The vaccine programme has weakened, but not broken that link.

“We urge the Government to keep a very close watch on the evidence as it emerges in the coming days, and to be ready to make the right call – whichever way it points – when the real decision day comes round next week.”

The Royal College of Nursing said protection is still required for frontline workers, with the virus remaining a “significant risk”.

Jude Diggins, the college’s interim director of nursing, policy and public affairs, said: “When Covid-19 cases are soaring across the UK, we must not lose the benefits of a successful vaccine programme to rash decisions. We must continue to protect our most vulnerable and frontline workers.

“This disease does not disappear on July 19. No available vaccine is 100% effective.

“Covid-19 will remain a significant risk to the public’s health and healthcare workers.”

She said public mask wearing has been “straightforward and well-established”, adding that the Government “will regret the day it sent the wrong signal for political expediency”.

Ms Diggins added: “After these steps, nursing staff need even greater protection than they have been afforded to date – they still need higher-grade masks.

“Political announcements must not cause yet more confusion in the health service and we will need clarity around public health measures.”