Around one in seven people in private households in England are estimated to have had coronavirus by mid-January 2021, the latest data shows.
According to the Office for National Statistics (ONS), this is up from an estimated one in nine people in December 2020 and one in 11 people in November.
The figures are the proportion of the population who are likely to have tested positive for antibodies to Covid-19, based on blood test results from a sample of people aged 16 and over.
The ONS found substantial variation in the proportion of people estimated to have tested positive for Covid-19 antibodies across the regions of England.
London was estimated to have the highest level of antibody positivity by mid-January (21.0% of people in private households), followed by the West Midlands (18.8%) and Yorkshire & the Humber (18.7%).
South West England was estimated to have the lowest level (8.3%), followed by South East England (10.2%) and Eastern England (10.8%).
Estimates for the other regions are North West England 18.1%, North East England 16.2% and the East Midlands 15.7%.
Sarah Crofts, Senior Statistician for the Covid-19 Infection survey said: "Household testing in England has detected a marked increase in the percentage of people testing positive for antibodies up till 18 January."
New cases, hospitalisations and deaths have been showing signs of declining in recent days, but at a far slower pace than during the first lockdown during spring last year.
The ONS also found in England and Scotland the age group that had the highest percentage of people testing positive for antibodies were those aged 80 and over.In Wales, this was reversed with the highest amount of antibodies present in 16-24 year olds.
In Northern Ireland it was 25-69 year olds.
The ONS also estimated that one in nine people in private households in Wales is likely to have tested positive for Covid-19 antibodies by mid-January, up from one in 14 in December.
For Scotland the estimate is one in 10, up from one in 13.
For Northern Ireland the estimate is one in 11, up from one in 14.