The UK reported 93,045 Covid-19 cases on Friday – as the daily infections record was broken for the third successive day.
The government said a further 111 people had died within 28 days of testing positive for Covid-19.
Separate figures published by the Office for National Statistics show there have now been 172,000 deaths registered in the UK where Covid-19 was mentioned on the death certificate.
On Thursday, the UK Department of Health reported 88,376 new cases, the highest daily tally reported since the start of the outbreak. That had followed an increase of 78,610 new cases on Wednesday, itself a record.
Figures from the UK Health and Security Agency suggest Omicron is now the dominant strain in England.
In Scotland, First Minister Nicola Sturgeon said Omicron was also the dominant strain and that a "tsunami” of cases was coming.
The new Omicron variant is believed to be fuelling the surge in coronavirus cases, with the real number of new infections thought to be as high as 200,000 per day.
The risk of reinfection with the Omicron is more than five times higher and it has shown no sign of being milder than Delta, a study by Imperial College London showed.
The results were based on UK Health Security Agency and National Health Service data on people who tested positive for Covid-19 in a PCR test in England between November 29 and December 11.
"We find no evidence (for both risk of hospitalisation attendance and symptom status) of Omicron having different severity from Delta," the study said, although it noted that data on hospitalisations remains very limited.
"Controlling for vaccine status, age, sex, ethnicity, asymptomatic status, region and specimen date, Omicron was associated with a 5.4-fold higher risk of reinfection compared with Delta," the study, which was dated December 16, added.
"This implies that the protection against reinfection by Omicron afforded by past infection may be as low as 19 per cent," Imperial College added in a statement, noting that the study had not yet been peer reviewed.
Prime Minister Boris Johnson on Friday said Britain was facing a “considerable wave” as he urged people to receive booster shots to stop the spread.
Mr Johnson has played down suggestions he is at odds with England's Chief Medical Officer Chris Whitty over advice to the public.
He also deflected questions over the future of his position as prime minister, insisting people want him to focus on fighting Covid-19.
During a visit to a vaccination centre in Hillingdon in London on Friday, Mr Johnson said Omicron is “a very serious threat to us now” and called on people to take their booster shots.
“We are seeing a considerable wave coming through and people have got to be prepared and they have got to understand what it entails,” he said.
Mr Johnson said he and Prof Whitty are on the same page on Covid, after some Tory MPs claimed experts are “running the show”.
Omicron variant - in pictures
-
Medical staff take care of a Covid-19 patient in the intensive care unit at the University Medical Centre Magdeburg in Magdeburg, eastern Germany. AFP -
Pedestrians on a pedestrian crossing in the Shibuya district of Tokyo, Japan. AP Photo -
Worshippers at the first of nine daily dawn masses before Christmas day at the St Joseph parish church in suburban Las Pinas city, Philippines. AP Photo -
The queue for a Covid-19 test at St Vincent's Hospital drive-through testing clinic at Bondi Beach in Sydney, Australia. EPA -
US President Joe Biden meets members of the White House Covid-19 Response Team to discuss latest developments related to the Omicron variant in the Roosevelt Room in the White House in Washington, DC. Reuters -
A mobile testing site near the NYU campus in New York. AP Photo -
Outdoor tables at a restaurant on Old Compton Street in Soho, London. PA -
A balloon vendor and Christmas shoppers in the centre of Cardiff, Wales. PA -
A healthcare worker prepares a dose of Moderna Covid-19 vaccine in Nairobi, Kenya. AFP -
Medical staff prepare an isolation ward for Covid-19 patients at a government hospital in Chennai, India. AFP -
Residents of the Soweto Home for the Aged social distancing during breakfast in Johannesburg. AP Photo -
Skiers ride a lift line on Mount Jahorina, Bosnia and Herzegovina. AP Photo
Asked about conflicting messages from the government and its advisers on socialising over the Christmas break, Mr Johnson said: “What both Chris Whitty and I are saying is that there is a big wave of Omicron coming through.
“People need to be prudent. You need to think about your budget of risk.”
A Cobra meeting will be held over the weekend with the devolved administrations to discuss the current variant threat.
The Prime Minister spoke with Scottish First Minister Nicola Sturgeon on Friday.
And a Downing Street spokesperson said: “The Prime Minister and the First Minister agreed on the importance of close collaboration for the benefit of citizens across the UK.
“They discussed the shared challenges including the economic disruption caused by Covid and will continue to work together.
“The Prime Minister confirmed UK Government will be convening a Cobra meeting over the weekend with counterparts from the devolved administrations to continue discussions.”
