The coronavirus “rule of six” has come into force in England, meaning any social gatherings of more than six people will break the law.
People face fines of up to £3200 ($5600) if they do not abide by the measure, which applies to indoor and outdoor settings and follows a rapid increase in the number of daily positive cases.
More than 3000 COVID-19 cases were recorded in the UK for the third day in a row on Sunday – the first time since May that cases were above 3000 on three consecutive days.
The new law comes amid concerns about an increase in cases in care homes and growing criticism of the NHS Test and Trace system.
Aside from limited exemptions including work and education, police will be able to disperse gatherings of more than six people and issue fines ranging from £100 to £3200.
Home Secretary Priti Patel said the recent rise in cases “makes it clear that more needs to be done to stop the spread of this disease”.
The rule applies across England and replaces the existing ban on taking part in gatherings of more than 30 people and the current guidance on allowing two households to meet indoors.
As of Sunday morning, there had been a further 3330 lab-confirmed cases of coronavirus in the UK.
Tough new lockdown measures were announced for parts of the UK on Friday as cases continued to rise and as the R number – the reproduction number of coronavirus transmission – climbed above one.