Easing coronavirus restrictions too soon will be a “recipe for disaster”, a doctor has warned, amid concerns for an NHS already struggling with a backlog of non-Covid patients.

Prime Minister Boris Johnson has come under pressure to move ahead with “freedom day” on June 21, given the uptake of Covid-19 vaccines in recent months.

Several frontline workers have already expressed fears about the impact of reopening in the coming weeks, with some describing the health service as still “on its knees” and at higher capacity than usual.

Dr Megan Smith, told the PA news agency: “Everyone in the NHS at the moment is kind of terrified.”

Dr Smith, who is also legal and policy officer for campaign group EveryDoctor, said the NHS is under pressure dealing with issues from the first waves of the pandemic, and could not cope with even a small spike in Covid patients.

She said: “Now patients have presented and a lot of them are presenting in a worse state.

“We’ve heard of hospitals effectively closing their waiting lists, which is unheard of.”

“Without question, there should be a pause,” she added.

“And in my view, there should be a look at whether there needs to be backtracking and have more restrictions in place.

“Obviously that is a deeply unpopular thing to say.”

Half of adults in the UK are now estimated to have received both doses of a Covid-19 vaccine, with three-quarters have received a single shot. However, Dr Smith said this may not be enough protection against the rising Delta variant.

The view echoed that of the Society for Acute Medicine, which warned that even a small increase in Covid-19 numbers could jeopardise plans to tackle the backlog of routine surgery.

“Any slight rise in numbers will put the latter into jeopardy, as hospitals will again lose any flexibility in how they manage their bed bases around infection control policies,” Dr Nick Scriven, immediate past president, said.

He added that there was “very significant concern” around the Delta – or Indian – variant, “especially around the potential for vaccinated staff to be asymptomatic carriers”.

With hospitals working through referrals, general practice has come under increasing strain.

Dr Emily Ball, a general practitioner in the North West, said GPs were “pretty broken and close to burnout”.

She told PA: “The biggest frustration is this idea that GPs haven’t been open, or have been trying not to deal with patients, when actually general practice is a bit of a mess.

“In March, we dealt with more patients than we ever have since records began. So the stuff we are doing is greater than ever, and unfortunately so is the amount of abuse we are taking.”

She said staff, who are working up to 15 hours a day to fit people in, are regularly sworn at by patients desperate to be seen, and the doors to her surgery were recently smashed in.

“We know there’s still a lot of kind of unclear messaging going on, and I think unfortunately is people’s behaviour has been relaxing,” she said.

“And then the beaches are packed, nobody’s wearing a mask, there’s no social distancing, and you just want to weep.

“The NHS is still in crisis and we cannot cope as it is. Unlocking poses a real threat to it just collapsing, and my biggest concern is patient safety.”

Dr Smith said it was easy to be “lulled into a false sense of security” by low numbers of Covid patients in hospital, adding: “We are all sitting here thinking, ‘oh god it’s going to happen again’.”

She continued: “It does feel as though a lot of the public has tried to go back to normal and has shut its eyes and ears to what is going on in hospitals.

“It feels a bit like the NHS is going to pay for everyone else’s freedom and pleasure.

“And those patients who will get infected and who will die for it will pay as well, but everyone else will be okay and that’s not really a position that I think is particularly morally defensible.

“I understand the people just want this all to go away but we’re adults here, and it’s not just going away.

“We need to be in it together because it’s just deeply unfair to make those working in the NHS and the proportion of families who will lose somebody bear the brunt of all of this.”