Health secretary Matt Hancock has told people it is "incredibly important" to follow new social gathering limits in England amid a surge in new coronavirus cases.
The warning comes as social gatherings of more than six people in England are set to be made illegal next week in a bid to tackle a sharp rise in new positive cases of coronavirus.
A further 2,420 people tested positive on Tuesday, bringing the total number of new cases in the UK to 8,396 since Sunday.
The new rules, set to be brought in on Monday, will apply in both public and private spaces, including parks, pubs and restaurants, and will only exclude households or support bubbles larger than six people.
Workplaces and schools are not covered by the new restrictions, and exemptions will be made for Covid-secure funerals and weddings, as well as some team sports.
Boris Johnson is set to unveil further details on the rule change at a Downing Street press conference later today, but speaking on Tuesday, he said: "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."
He added: "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."
The simplification of the social gathering rules comes amid concerns that the slew of rules announced by ministers since the beginning of the pandemic had left people confused.
And Matt Hancock said the decision had been made to delay the rule change until Monday so that people had a chance to read and understand them.
"We need to take this action. We have seen a rise in cases," he told Sky News.
"We need everyone to see the new rules and read them, that's why it is coming into force on Monday.
"Every single person in the country needs to know what they are so we can together keep a grip on the virus.
"Abiding by the rules is absolutely vital to protect life."
He added: "Everybody understands how important it is that we together keep this under control. We can't do it individually because of the nature of the disease.
"It is incredibly important that everybody follows these new rules.
"We will be bringing in strict enforcement so that they can be followed."
From Monday, anyone found flouting the rules will be liable for a £100 on-the-spot fine, which will double for repeat offences up to £3,200.
The decision to impose the new restrictions comes ahead of the return of universities, with ministers pointing to rising infection rates among younger people.
On Tuesday, Chris Whitty, England's chief medical officer, urged young people to follow the social distancing rules saying without them "Covid comes back".
"We have through the extraordinary efforts of the whole population got Covid rates right down. They are now rising again especially in those aged 17 to 29," he tweeted.
"If we stop social distancing Covid comes back. We all need to protect others."
A government spokesperson said: "The government, chief medical officer and chief scientific adviser have jointly agreed that urgent action is necessary after seeing the number of daily positive cases rise to almost 3,000 recently."