People walk past signs for a COVID-19 testing clinic in London, Britain, on Dec. 9, 2021. (Photo by Stephen Chung/Xinhua)

At least one person has died with the Omicron variant in Britain, British Prime Minister Boris Johnson confirmed Monday.

"Omicron is producing hospitalizations and sadly at least one patient has been confirmed to have died with Omicron," the prime minister said during a visit to a vaccine clinic in Paddington, west London.

Earlier, British Health Secretary Sajid Javid said there were 10 people in hospital in England with Omicron, but warned that cases, hospital admissions and deaths will rise. According to the UK Health Security Agency (UKHSA), their ages range between 18 and 85.

The British health secretary has also warned the Omicron variant is "spreading at a phenomenal rate" and infections are continuing to double every two to three days. The rate of its spread is "something we've never seen before", he told Sky News.

"It's pretty clear that the world can expect a tidal wave of new infections. How much of that translates into hospitalizations and mortality is still unknown. It seems that it's either milder or the existing levels of protection do give some protection. But just the sheer number of infections is highly concerning," Rasmus Bech Hansen, the chief executive of London-based Airfinity, a global health intelligence and analytics provider, told Xinhua in an online interview.

Another 1,576 Omicron cases have been found in Britain, the biggest daily increase since the COVID-19 variant was detected in the country, taking the total cases found in the country to 4,713, the UKHSA confirmed Monday.

Britain reported 54,661 new coronavirus cases, bringing the total number of coronavirus cases in the country to 10,873,468, according to official figures released Monday.

The country also reported a further 38 coronavirus-related deaths. The total number of coronavirus-related deaths in Britain now stands at 146,477, with 7,372 COVID-19 patients still in hospital.

Long queues are forming at COVID vaccination centers on Monday and there are widespread reports of the National Health Service (NHS) booking site crashing as people scramble to get their booster jabs ahead of Christmas.

The prime minister launched Sunday night a "national mission" called Omicron Emergency Boost. The health secretary has urged people to get their booster jab as soon as possible, warning that "two doses are not enough, but three doses provide excellent protection against symptomatic infection."

The UK COVID alert level has been raised from Level 3 to Level 4, the second highest level, "in light of the rapid increase in Omicron cases", the four British chief medical officers said in a joint statement Sunday.

More than 89 percent of people aged 12 and over in Britain have had their first dose of vaccine and more than 81 percent have received both doses, according to the latest figures. More than 41 percent have received booster jabs, or the third dose of a coronavirus vaccine.

To bring life back to normal, countries such as Britain, China, Germany, Russia and the United States have been racing against time to roll out coronavirus vaccines.