The new study asked site investigators to categorise the deaths as having either no evidence of delayed access to medical care contributing to them, or whether it was a probable or possible factor.

Pathologists are given access to coroners’ reports when carrying out post-mortems, which include testimonies from families, doctors and medical notes, aiding the categorisation.

For delayed access to care to be classed as a probable factor in the death there needed to be “clear evidence that lockdown prevented the patient obtaining medical care, or the patient contacted medical services and was advised to self-isolate, subsequently dying from a potentially treatable condition”, the study said.

Ian Roberts, professor of cellular pathology at the Oxford University Hospitals NHS Foundation Trust and a study author, said the research had been triggered by his own experience of carrying out post-mortems during the first lockdown.

“I found myself doing a number of autopsies where the deceased had contacted medical services with symptoms related to their death, but instead of being admitted to hospital, which they normally would have been, they were told to self-isolate at home and didn’t have any access to care,” he said.

In one case, a young diabetic was ill, vomiting and had fever but was told to self-isolate, he said. They subsequently died from diabetic ketoacidosis, a treatable but serious condition, when the body starts breaking down fat too fast, which can cause the blood to become acidic.

“I think it’s clear from our study that the excess deaths during the Covid lockdown is at least in part due to reduced access to medical care,” Prof Roberts said.

‘Exactly what we’ve been seeing all along’

Dr Charles Levinson, the chief executive of the private GP company DoctorCall, said the findings were “exactly what we’ve been seeing all along”, adding: “It’s nothing new, but it is a scandal that the effects of lockdown haven’t been properly taken into account,” he said.

He said “you can’t have a black and white rule” when it comes to future lockdowns, but said: “I think that what’s important is that it’s not thought that lockdown is a free alternative, an easy option without consequences, because it isn’t.”

Around 13 to 14 per cent of all deaths undergo a coroner’s autopsy in England each year. Dr Lucy Pocock, an academic GP at the University of Bristol, said care should be taken not to generalise the study findings to other deaths as post-mortems only occur in a small proportion.

“In order for us to know if this phenomenon was widespread and affected more of the people who died during the lockdown, we would need to interrogate the medical records of a sample of people who died who didn’t have a post-mortem,” she said.