Britain has suffered the deadliest outbreak of coronavirus in Europe but a new study suggests the health authorities are overestimating the toll by including people who died long after they recovered.

More than 45,000 deaths have been recorded in patients who tested positive for coronavirus, a grim figure that has sparked accusations that Prime Minister Boris Johnson's government bungled its response.

But an article for the Centre for Evidence-Based Medicine published Thursday reveals a statistical anomaly in the way data is gathered by the public health agency in England. Every time a patient dies, the central register of the state-run National Health Service (NHS) is notified, authors Yoon K Loke and Carl Heneghan note.

They say that in compiling its daily coronavirus toll, Public Health England (PHE) simply checks its list of lab-confirmed cases to see whether they are still alive. "A patient who has tested positive, but successfully treated and discharged from hospital, will still be counted as a COVID death even if they had a heart attack or were run over by a bus three months later," they write.

They suggest this could explain variations in the English daily toll, and why deaths there have not fallen in the same way they have in Scotland, Wales and Northern Ireland, which collect their own data. Under this approach, "no one with COVID in England is allowed to ever recover from their illness", the article says -- and the ultimate death toll will include every one of the 292,000 people who has had the virus.

"It's time to fix this statistical flaw that leads to an over-exaggeration of COVID-associated deaths," it says. "One reasonable approach would be to define community COVID-related deaths as those that occurred within 21 days of a COVID positive test result."

However, the daily-updated coronavirus toll is only one way of measuring deaths and was already known to have limitations because it does not include people who did not have access to a virus test. Some analysts suggest the so-called "excess deaths" figure is the best way of assessing the true figure.

The Office for National Statistics says 54,000 more people died in the year to July 3 in England and Wales than the five-year average for that period.