England recorded the most excess deaths in Europe in the first half of 2020
Britain has banned people from different households in Manchester and stretches of northern England from meeting indoors because of a spike in coronavirus infections.
Health Secretary Matt Hancock said restrictions were being tightened slightly for millions of Britons because people were "meeting and not abiding to social distancing".
"We take this action with a heavy heart, but we can see increasing rates of Covid across Europe and are determined to do whatever is necessary to keep people safe," Hancock said on Twitter.
The measure came into effect from midnight on Thursday.
New UK statistics comparing how the virus struck various regions showed England recording the most excess deaths in Europe in the first half of 2020.
Spain registered the second-highest toll in excess deaths - defined as the number of fatalities registered in excess of the five-year average - while Scotland saw the third-worst figures.
Britain's official virus death toll stands at 45,999 but is believed to be as high as 65,000 if excess deaths are used as a guide.
Britain's devolved health structure means England is following slightly different preventive measures from those in Scotland or Northern Ireland and Wales.
England has lifted most of its restrictions nationally but imposed local store closures around the central city of Leicester at the end of June.
Hancock said Leicester would now follow the same ban on meetings between different households being applied to Manchester and parts of West Yorkshire and East Lancashire.