Britain's government reported 53 135 new cases of Covid-19 on Tuesday, the highest number since mass testing started in mid-2020 and up sharply from the previous record of 41 385 set on Monday.
The number of new deaths recorded within 28 days of a positive Covid test also rose to 414 from Monday's 357, taking the total since the start of the pandemic to 71 567.
Britain vies with Italy for Europe's highest death toll from the disease and is now battling a new variant of Covid which scientists say can spread more rapidly.
Just under half of England's population, centred around London and neighbouring regions, is currently under the tightest form of Covid restriction. Under these rules non-essential shops and most other businesses are closed to the public, and almost all face-to-face socialising is prohibited.
However in most of Britain rules were relaxed to allow families to meet on Christmas Day, which many health officials said risked causing a spike in Covid-19 infections.