The number of Covid infections has launched to its highest level since last summer. At the same time, the nation fights its worst flu season in a decade with desperate scenes in the NHS.
Figures from the Office of National Statistics showed the number of people likely to have coronavirus over Christmas was a huge 2.9million.
The concerning number is more than double the number at the start of December and the highest total since mid-July.
Michelle Bowen, ONS head of health surveillance, said infections have risen across the whole of the UK, with levels in Northern Ireland now at their highest since March 2022.
She added: "Across English regions, infections have increased in the North East, Yorkshire and the Humber, the East Midlands, the East of England, the South East and the South West.
"Cases have also increased in those aged two to school Year 6, and those aged 50 years and over."
Around one in 20 people in England are likely to have had Covid-19 over the festive period, along with one in 18 in Wales and one in 16 in Northern Ireland.
The prevalence of the virus is slightly lower in Scotland, at one in 25 people.
It comes as viral experts warned a new Covid sub-variant is expected to take off in the UK- and it's nicknamed the Kraken.
Named 'XBB.1.5', the sub-variant is an offshoot of the Omicron variant which ran riot in Christmas 2021.
University of Warwick virologist Professor Lawrence Young believes the UK is not prepared for a new wave, despite some experts believing the variant will spread in the UK.
The NHS is currently in crisis over staff shortages, as well as huge case numbers of flu and winter illnesses.
Young also told BBC Radio 4 that "we do need to keep an eye on what’s going on in terms of the spread of this particular variant".
Covid Zoe app founder Professor Tim Spector said XBB.1.5 "could be the new variant to watch out for.”
In the US, the number of XBB.1.5 cases rose from four per cent to 41 per cent of Covid infections.
Maria Van Kerkhove, the WHO’s technical lead on Covid, said: “Our concern is how transmissible it is.
“The more this virus circulates, the more chances it will have to change.”
“We are concerned about its growth advantage in particular in some countries in Europe and in the US... particularly the Northeast part of the United States, where XBB.1.5 has rapidly replaced other circulating variants.”