LONDON, Jan 22 (Reuters) - The COVID-19 variant identified in England last month could carry a higher risk of causing death although data is limited, according to one of the government's scientific advisory groups, ITV political editor Robert Peston said on Twitter on Friday.

While the new variant is more contagious, Britain's chief health and science officials have so far said there was no evidence that it was more lethal or caused more serious illness.

However, Peston said the government's New and Emerging Respiratory Virus Threats Advisory Group (Nervtag) had now concluded it "may be a bit more lethal than the existing strain".

He cited a statement from Neil Ferguson, an Imperial College professor and Nervtag member, as saying: "It is a realistic possibility that the new UK variant increases the risk of death, but there is considerable remaining uncertainty."

No one was immediately available for comment from Britain's Department of Health, which covers Nervtag.

The statement cited by Peston set out a 1.3-fold increased risk of death with the variant, but also highlighted that only some types of testing could specify which variant of the virus a patient had contracted.

"The big caveat is that we only know which strain people were infected with for about 8% of deaths," Peston quoted Ferguson as saying, also setting out further limitations on the available data. (Reporting by William James; Editing by Michael Holden and Alison Williams)