The government’s frightening and unproven claim that the new variant of the Covid-19 virus is 30 per cent more lethal is challenged by a leading member of the key body monitoring the disease. He says it is wrong to “exploit it to increase public fear.”

Professor Robert Dingwall, who sits on the New and Emerging Respiratory Virus Threats Advisory Group, told Reaction:

“The 30 per cent more lethal claim about the virus rests on a very fragile and uncertain base of evidence. NERVTAG has expressed limited confidence in this figure, which should not be the basis for public alarm.”

He continued: “It is right not to hide possibly bad news but it is also quite wrong to exploit it to increase public fear and to try to shut down debates about the exit strategy from the current restrictions.”

“If, as seems likely, the vaccines are as effective against the Kent variant as the previous one, then any increase in risk, which is not proven, is only a temporary problem that will disappear as the vaccine programme rolls onward.”

Dingwall stressed that he is speaking in a personal capacity and not on behalf of NERVTAG. But his comments shed light on the debates within NERVTAG and SAGE over when to begin reducing restrictions, with some scientists wanting to maintain controls for as long as possible.

At a press conference in Downing Street on Friday, Boris Johnson said that the new Kent strain of the virus may be more lethal. He said: “We’ve been informed today in addition to spreading more quickly, it appears there is some evidence the new variant may be associated with a higher degree of mortality.”

He suggested that the virus could be as much as 30 per cent deadlier than the previous strain.

The Chief Medical Officer Chris Whitty and the government’s chief scientific advisor Patrick Vallance, stressed that the data, which feeds into the government’s decision was uncertain, speaking at the same conference.

The story initially emerged on Twitter after ITV’s Robert Peston reported: “The government’s New and Emerging Respiratory Virus Threats Advisory Group (or Nervtag) has concluded that the new Covid-19 strain may be a bit more lethal than the existing strain.”

He was briefed about the story by the infectious disease modeller Neil Ferguson, who told Peston: “It is a realistic possibility that the new UK variant increases the risk of death… So for 60-year-olds, 13 in 1000 might die compared with 10 in 1000 for old strains.”

Given the uncertainty of the data, it is unclear why Ferguson, a controversial figure, thought it necessary to brief Peston before the relevant information had been properly disclosed. Critics may say that in a public health crisis, transparency and predictability in government decision-making is absolutely vital both to preserve public trust and to ensure proper accountability.