Health authorities in England have identified 38 cases of a new coronavirus strain that has a key mutation thought to reduce the effectiveness of vaccines, the government said on Tuesday.
"There is currently no evidence that this set of mutations causes more severe illness or increased transmissibility," said Prof Yvonne Doyle, medical director at Public Health England.
The health body said the cases were dispersed across England.
The variant, known as B1525, has the E484K spike protein mutation, which is also in the South African variant and could undermine the effectiveness of vaccines.
The B1525 variant has also been detected in Nigeria, Denmark and Canada, Public Health England said.
Meanwhile, data released on Tuesday showed Britain recorded another 799 deaths from people who tested positive for Covid-19 within 28 days, and 10,625 more cases.
The daily figure for deaths was up from the 230 recorded on Monday, but Monday's data tends to be distorted by delays in weekend reporting.
The official figures showed 15.6 million people have had a first dose of a vaccine, while 546,165 have had a second.
Every adult in the UK could receive both doses of a coronavirus vaccine by August or September, the head of the country's vaccine taskforce told Sky News on Tuesday.
"We're probably talking August time or September time all done, maybe sooner if we need to," Clive Dix said.