From that URL:

"Robert Dingwall, from the New and Emerging Respiratory Virus Threats Advisory Group (Nervtag), said the rule was 'conjured up out of nowhere'. The sociology professor at Nottingham Trent University said scientific evidence supports a one-metre gap, but the two-metre advice was a 'rule of thumb'.

Nervtag feeds into the Scientific Advisory Group for Emergencies (Sage), which is spearheading the [British] government's pandemic response."

Laura Ingraham may indeed have been correct when she claimed during Monday's broadcast[May 4 on Fox News]:

"Although, intuitively, I think it probably seemed like social distancing would be necessary, there was no real scientific basis for believing that since it had never been studied,"