The studies compared hospitalization and death rates among people infected with the variant and those infected with other variants.
A new Covid-19 hotel quarantine system for arrivals from 33 "red list" countries, meant to limit the spread of new variants of the virus, appears to be working smoothly a few hours after it was introduced, Hancock said.
Despite that increased risk, the British scientists said, "the absolute risk of death per infection remains low".
In the report, which evaluated multiple studies, the scientists estimated that the strain, known as B.1.1.7, could be 30 percent to 70 percent deadlier than the original virus.
There are still many unknowns: The data available to study has noteworthy gaps among critical demographics, such as nursing homes, and provides an incomplete tally of infections, a problem persisting throughout the pandemic.
Scientists have warned that lessons must be learned from the "mistakes" made previously in relaxing lockdown measures too fast.Professor Neil Ferguson, who advises the Government as part of the New and Emerging Respiratory Virus Threats Advisory Group (Nervtag), warned that more information is needed about how effective vaccines are going to be.
Johnson, who will set out his plan to lift lockdown on February 22, said the rates of infection were still very high and that too many people were still dying.
He said: "The modelling we and other groups and universities in the United Kingdom have been doing would suggest there probably is leeway to reopen all schools".
The rapid spread of variants led Britain in January to institute a comparatively longer and stricter lockdown than the country's previous ones.
"When you have a large level of circulation, when you've got a lot of disease, invariably the vulnerable suffer so that's why we want to drive it right down, keep it right down", he said. Scientists have also expressed concern that the variant could be developing a mutation that would help it evade vaccines.