Rules on physical distancing to curb the spread of coronavirus are based on 'outdated science', Oxford University academics have said.

Writing in The British Medical Journal, the team of researchers said instead of a one-size-fits-all approach to social distancing, there should be 'graded recommendations' for different distancing rules in different settings.

They added this would 'potentially enable a return towards normality in some aspects of social and economic life'.

The idea is distancing rules should take account multiple factors that affect risk, including type of activity, indoor versus outdoor, level of ventilation and whether face coverings are worn.

Other important factors include duration of exposure, susceptibility of someone to infection and viral load of the transmitter.

They wrote some of the research which points towards two metres being the optimal safe distance was first published in 1897.

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And research from the 1940s is 'entrenched' in the assumed scientific basis of the one to two metre rules to prevent coronavirus spread, despite 'limitations in accuracy' of the early studies, they wrote.

Newer studies have found that in certain circumstances, droplets from a forceful sneeze or cough could spread up to eight metres.

Meanwhile they argue that much of the research is based on droplet size without accounting for exhaled air.

In reality transmission is much more complex, they wrote.

Nicholas Jones,from Oxford University’s Nuffield Department of Primary Care, said: “Current rules on safe physical distancing are based on outdated science.

“Distribution of viral particles is affected by numerous factors, including air flow.

“Evidence suggests Sars-CoV-2 may travel more than two metres through activities such as coughing and shouting.

“Rules on distancing should reflect the multiple factors that affect risk, including ventilation, occupancy, and exposure time.”