Doctors have postponed more than 2m operations after non-emergency surgery was cancelled for at least three months to free up beds for coronavirus patients.

The mounting backlog of procedures could cost the NHS £3bn to work through and may require many of the 20,000 doctors and nurses who have returned to the health service to stay on once the Covid-19 crisis has been brought under control.

According to NHS England, postponing the planned operations, which typically cost £1bn per month, has released 12,000 beds for patients who have fallen ill after contracting the virus.

“We are probably only delivering around on- third of our usual surgical activity and that’s nearly all for emergency and very urgent surgery. In the short term, we have to do a really major catch-up exercise to stop this backlog causing harm,” Prof Derek Alderson, the president of the Royal College of Surgeons in England, told the Sunday People.

Operations for hip and knee replacements, cataracts and hernias have all been delayed to make beds available to cope with coronavirus cases. Outpatient procedures are also on hold.

The disruption to operations will have consequences for scores of patients, ranging from those with cancer, whose tumours may grow while they are waiting for surgery, to those who are less able to exercise and become unfit in the run-up to physically demanding operations.

“The consequences are really serious,” Alderson said. “There are some patients who have cancers that are usually slow-growing but this may impact on long-term survival. A patient’s condition may deteriorate so they are no longer fit for the operation. Someone may be waiting for a hip replacement and may not be able to exercise and become even less fit for surgery. They may become addicted to opiates to manage their pain. Then there are all the mental health consequences.”

The warning follows concerns raised by Cancer Research UK that the number of patients with suspected cancer who are being referred to hospital specialists has fallen dramatically. The charity believes more than 2,000 cancers are being missed each week and that many will become inoperable if they remain undetected. As estimated 400 cancers a week are being missed because normal screening programmes for breast, cervical and bowel cancer have been suspended.

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An NHS spokesperson said: “While NHS staff have pulled out all the stops to manage coronavirus cases, they have continued to work hard to ensure patients can safely access services.

“Next week we will set out new guidance on redeploying some of the treatment capacity that was created while the number of Covid-19 patients rose sharply. A public information campaign is reminding people the NHS remains open for business. It is important that non-Covid-19 patients can still safely access care and treatment.”