The new law will apply to both indoor and outdoor settings, the Government announced on Tuesday evening.
Boris Johnson will hold a press conference at Downing Street on Wednesday afternoon to explain the rules in more detail.
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Here is everything you need to know.
When is Boris Johnson’s speech today?
The Prime Minister will reportedly hold a press conference from Downing Street at 4pm, after his PMQs appearance.
You will be able to watch it live on BBC News and Sky News.
Mr Johnson said on Tuesday: “We need to act now to stop the virus spreading. So we are simplifying and strengthening the rules on social contact – making them easier to understand and for the police to enforce.
“It is absolutely critical that people now abide by these rules and remember the basics – washing your hands, covering your face, keeping space from others, and getting a test if you have symptoms.”
What are the new rules?
From Monday 14 September, social gatherings of more than six people in England will be banned by law.
This applies to private homes and gardens, and all public spaces such as pubs, restaurants and parks.
It does not apply to schools or workplaces. Covid-secure weddings and funerals – at which you are allowed a maximum of 30 people – are also exempt.
Organised team sports are still allowed.
Households and support bubbles of more than six people are also unaffected.
People who refuse to comply with police orders could be fined £100, doubling with each offence to a maximum of £3,200 per person.
The rule itself has not actually changed. Previously the Government only allowed meetings of up to six people from different households – or two households of any size.
However, the police only had power to break up groups of over 30.
Why have restrictions been tightened?
More than 2,400 new infections were recorded on Tuesday, up from 1,295 a week prior.
This followed two days where there were just shy of 3,000 cases – the highest rate since May.
The UK’s rate of infection per 100,000 people over a seven-day period has also risen above 20 – the benchmark the Government has been using for introducing quarantine rules for other countries.
‘Hands. Face. Space’
The Government is also launching a new information campaign to highlight how everyone can help stop the spread of the virus by remembering to wash their hands, cover their face and make space.
The “Hands. Face. Space” campaign will run across TV, radio, print, out of home, social and digital display advertising, with a new video being released to show how coronavirus spreads indoors.