A record-breaking 1.7 million people in the UK had Covid-19 in just one week as Omicron continues to rip across the country.
The total is the highest since comparable figures began in autumn 2020, the Office for National Statistics said.
The percentage of people infected varies widely across the UK, with England topping the four nations with 2.83% testing positive between between 13 December 2021 and 19 December 2021.
Wales hit 2.3%, Northern Ireland 2.45% and Scotland the much lower figure of 1.5%.
The worst hit area in England was London, where one in 20 people caught the virus, while that total dropped significantly in the North East to one in 55.
Around one in 35 people in private households in England had Covid-19 in the week to December 19, up from one in 45 in the week to December 16.
One in 35 is the equivalent of about 1.5 million people and is the highest number since the ONS began estimating infection levels for England in May 2020.
The figures show just how infectious Omicron is, and now how widely spread the mutant strain has become in the UK.
Yesterday the country endured a record number of daily infections when 119,789 cases were reported in just a single 24 hour period.
On the positive side of things, Omicron appears to produce a milder form of the illness than previous forms of coronavirus.
There is a 20% to 25% reduced chance of a hospital visit and at least a 40% lower risk of being admitted overnight with the new mutant strain than Delta.
The improved outlook was worsened significantly for those who are not vaccinated.
Such eye-watering high levels of infection are taking their toll, even if they are not impacting hospitalisation rates as much as feared.
More than 600,000 people will be forced to isolate with Covid across the UK on Christmas Day, potentially ruining their festive plans.
As well as being throwing a spanner in the Christmas works, this could prove a massive obstacle for the NHS.
The number of staff days lost to Covid across the NHS in England hit 124,855 last week, a 38% jump from the 90,277 of the week before.
Key services may prove very difficult to manage if too many staff are taken ill or forced to isolate.
Chris Hopson, the chief executive of NHS Providers, said: “These figures show how Omicron is having a tangible real-time impact on a service that was already operating beyond full stretch.
"This is a big worry for trust leaders.
"Absences due to Covid-19 are up nearly 40% and with community infections surging ahead, that figure may well get worse before it gets better.”
