Gatherings of more than six are being banned to try to halt a second wave of coronavirus.
In his first reversal of the easing of national lockdown, Boris Johnson last night warned a surge in cases must not be allowed to get out of control.
From Monday it will be illegal to assemble in groups of seven or more anywhere in England, whether indoors or out.
The 'rule of six' is a dramatic reduction on the limit of 30 put in place on July 4.
Police will be encouraged to break up larger groups and issue £100 fines, which will then double on each repeat offence up to £3,200.
Only schools, workplaces and a limited number of other locations will be exempt.
Announcing the new restrictions, Mr Johnson 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.
'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.'
As the move prompted fears a wider and more damaging lockdown might follow:Oxford and AstraZeneca's COVID-19 vaccine trial is put on hold for safety reasons after a British volunteer had a 'serious' reaction that could have been caused by injection Business leaders, MPs and scientists told the Prime Minister not to lock Britain down again, with one think-tank warning a second shutdown would be 'catastrophic'. The daily Covid death toll reached 30 yesterday – the most in six weeks; Health bosses apologised for testing system failures after laboratory backlogs left many people unable to book; The first 'credible' cases of reinfection by coronavirus are starting to be seen, Health Secretary Matt Hancock told MPs; Aviation minister Kelly Tolhurst was quietly replaced amid continuing fury at the lack of coronavirus tests at airports; The number of patients waiting for an organ transplant has risen to a five-year high because of the pandemic;
The Department of Health announced the significant hike in deaths but said it did not include Northern Ireland which is yet to report its figures
Boris Johnson will ban social gatherings of more than six people, both indoors and outdoors, across all of England from Monday
Boris Johnson was last night urged to think very carefully before imposing a new lockdown in response to a spike in virus cases.
Business leaders, MPs and scientists told the Prime Minister to consider other options first, with one think-tank warning a second shutdown would be 'catastrophic'.
Concern within government was prompted by figures on Sunday showing there had been 2,988 new infections in the previous 24 hours, the highest daily rate since May 22.
Monday's numbers were at a similar level, with an additional 2,948 positive cases up to 9am, a jump from the 1,175 reported on Saturday. The latest death toll of 30 was the highest in six weeks.
But Christopher Snowdon of the Institute of Economic Affairs said: 'With UK case numbers at a fraction of where they were back in March, a second lockdown would be catastrophic and should be avoided.
Phase 3 trials for the coronavirus vaccine being developed by Oxford University and AstraZeneca have been placed on a hold after a 'serious adverse event' was reported in a participant in the UK.
Serious adverse events are suspected reactions to vaccines or drugs that require hospitalization, are life-threateningly or deadly.
It's unclear what the exact nature of the reaction was, but a person familiar with the matter told Stat News that the person is expected to recover.
Trial holds are not uncommon, but it is a blow to worldwide hopes for a shot to be ready in the coming months, as the AstraZeneca shot was considered by many - including the World Health Organization - to be the leading candidate worldwide.
Development of the AstraZeneca vaccine and eight others in phase 3 trials is being closely watched in the hopes they can stem the coronavirus.
It comes after vaccine developers - including AstraZeneca - pledged not to cut corners on safety and efficacy testing, despite US President Trump's urgent push for the Food and Drug Administration (FDA) to give emergency approval to a vaccine ahead of the November 3 election.
Ministers were shocked on Sunday when virus cases doubled to almost 3,000 – the highest figure since May.
They have used local lockdowns to control flare-ups and in Bolton the rules were tightened again yesterday, with a 10pm curfew on hospitality venues and a ban on dining out.
Downing Street said the surge appeared to be driven by 'young people, often in affluent areas'.
The PM's spokesman said similar outbreaks among the young in the United States and Europe had spread to older people a few weeks later, with deadly effect. He added: 'We need to ensure that doesn't happen here.'
The clampdown will dismay some Tory MPs who are urging the Government to press ahead with the reopening of society to avoid economic meltdown. But a Government source last night insisted the rule of six was needed to head off the danger of a wider lockdown.
Mr Johnson will underline the message at a press conference this afternoon, where he will be flanked by Chief Medical Officer Chris Whitty and Chief Scientific Adviser Sir Patrick Vallance.
In a sober briefing to the Cabinet yesterday, the two scientists warned ministers the R-rate had risen above one, meaning the virus was spreading exponentially again.
Today's change will mean an end to large family gatherings and big congregations in parks and pubs. Christmas family reunions are also under threat.
The move follows a conference call between the Prime Minister and police chiefs, who said the law had to be made simpler if their officers were to enforce it.
Police will now be encouraged to step up patrols and break up large groups.
Yesterday Mr Hancock said the recent spike in cases served as a reminder to the nation that the virus 'remains a threat'.
He stressed that social distancing was the first line of defence and said he was concerned about the situation in France and Spain.
Britain could be subjected to a nationwide curfew with businesses forced to shut from 10pm, it has been reported.
Punters in Bolton were yesterday told to down their pints before they were kicked out of pubs at the dawn of a new lockdown, amid desperate efforts to stop partying young people fuelling a surge in coronavirus cases.
Health Secretary Matt Hancock announced bars and restaurants in the city will only be allowed to serve takeaway and must close between 10pm and 5am.
The Daily Telegraph reports that ministers are now considering extending the 'curfew' to the whole country, after the seemingly successful measure was introduced in Belgium.
Mr Hancock has said that Bolton was host to 120 cases per 100,000 people, with contact tracing revealing that the rise was fuelled by Britons in their 20s and 30s spending time in pubs.
A senior Government source says ministers have discussed the possibility of extending the curfew to the entire country.
In France the hospitalisation rate has trebled in a month while in Spain it has increased 15-fold since July.
A new campaign has also been launched to encourage people to help stop the spread of coronavirus.
The 'Hands Face Space' campaign urges people to ensure they have washed their hands, used a mask where appropriate and maintain social distancing.
The campaign states that these are the three most effective ways the public can contain the spread of the virus.
The advert highlights how the virus spreads in indoor setting - which is particularly pertinent as winter approaches.
England's chief medical officer professor Chris Whitty said: 'As we approach winter and inevitably spend more time indoors, we need the public to keep following this important advice to control the spread of the virus.
''Hands. Face. Space' emphasises important elements of the guidance we want everybody to remember: wash your hands regularly, use a face covering when social distancing is not possible and try to keep your distance from those not in your household.
'Following these simple steps could make a significant difference in reducing the transmission of Covid-19 and help protect you and your friends, colleagues and family from the virus.'
The campaign highlights how the novel coronavirus can live for more than 24 hours in indoor environments - it is not likely to survive for long periods of time on outdoor surfaces in sunlight. Regular hand washing and the use of hand sanitiser can also help reduce a person's risk of catching the virus and passing it on.
It demonstrates how people's respiratory droplets can spread and how wearing a mask can reduce dispersal of droplets.
And it shows how maintaining a safe distance means the virus is less likely to be transmitted.
The Police Federation of England and Wales urged the Government to 'play its part' through the public information campaign after 'so many changes in legislation'.
The developments come amid reports that the Government could soon launch a crackdown on young people spreading coronavirus,
The UK reported 30 more Covid-19 deaths on Tuesday - the highest one-day total for six weeks - as ministers warned the nation faces more lockdown misery unless social distancing rules are obeyed.
Boris Johnson and Matt Hancock joined medical experts in delivering a desperate appeal for 20 and 30-somethings to rein in their behaviour, amid growing alarm over a surge in cases.
In a potential sign of things to come for the rest of the country, the Health Secretary announced that pubs in Bolton must shut their doors to stem a flare-up.
With immediate effect, they can only serve takeaway, and are obliged to close between 10pm and 5am.
The prospect of banning gatherings of more than six people, which was mooted by some earlier this week, immediately sparked anger from Tory MPs who pointed out that infection levels remain extremely low.
One former minister told MailOnline it would be 'dreadful and disproportionate', an 'enormous intrusion into private life' and 'rule by directive'.
However, the latest daily death total of 30 is considerably higher than the three recorded the day before.
Although the statistic is higher than recent weeks scientists have cautioned against reading too much into one-day fluctuations and have said that broader trends are a better indicator of the situation.
There were 13 fatalities recorded on Thursday last week and a spell of three days that saw a total 44 in the last week of August.
The Government has been fearful hospitalisations will soon begin to rise as a result of rising infections, despite scientists reassuring that most cases are among younger, healthy generations.
Data from Public Health England shows that more than 40 per cent of coronavirus tests done in hospitals were positive in March and April but this has now plummeted and remains below 2.5 per cent in both hospitals and the community. This shows that there remains only a small proportion of people with the symptoms of coronavirus who actually have it
But European nations are only seeing a fraction of the weekly admissions they had during the peak of the pandemic, raising questions about whether it can really constitute a 'second wave'
Coronavirus hospital admissions could start to rise in the UK in three weeks, data from other European countries suggests. When Spain, France and Belgium hit 18 cases per 100,000 (which the UK did on Sunday) they then saw admissions increase by up to four-fold
MailOnline analysis shows infections have surged from 9.2 to 28 cases per 100,000 since July 4, 'Super Saturday', in those aged 20 to 29 in England
At the same time, cases in over 80 year olds have dropped drastically since the height of the pandemic, when they made up the majority of Covid-19 cases, and have halved since July. Infections have stayed stable among those in their 60s and 70s, while very slightly increasing in those between the ages of 40 to 59 years old
Cumulative cases in those aged between 10 to 19 and 20 to 29 over the course of the pandemic. It shows cases have increased from July 5
Cumulative cases in those aged between 70 and above 80 over the course of the pandemic. It shows cases have continued to decline over the summer
Wales's health minister has said local lockdown in the county borough of Caerphilly will not be lifted until October 'at the very least'.
People will not be allowed to enter or leave the area without a reasonable excuse after the restrictions come into force at 6pm on Tuesday.
Everyone over the age of 11 will be required to wear face coverings in shops – the first time this will be mandatory in Wales. Meetings with other people indoors and extended households will not be allowed, while overnight stays have also been banned.
Lockdown restrictions on household visits across western parts of Scotland have been continued for a further week – as well as being extended to other council areas.
Measures – originally introduced in Glasgow, East Renfrewshire and West Dunbartonshire – now also apply to East Dunbartonshire and Renfrewshire.
The restrictions bar people from visiting separate households in these parts of the country, while also prohibiting them from visiting homes in other local authorities which have not been impacted.
The measures also mean indoor visits to hospitals and care homes will be limited to essential visits only to protect the most vulnerable.
Hospitality venues are being restricted to takeaway-only in Bolton as part of new measures to curb the spread of Covid-19 in the town, Health Secretary Matt Hancock has told MPs.
Bolton Council said on Saturday it was introducing tougher measures 'with immediate effect', with people asked not to mix with other households in any setting, either indoors or outdoors, and to only use public transport for essential purposes.
The council said the new restrictions aim to prevent a local lockdown, after the town's infection rate increased to 99 cases per 100,000 people per week – the highest in England.
Those aged between 18 and 49 account for more than 90 per cent of the cases, the local authority said.
Parts of Greater Manchester, East Lancashire, Preston, and West Yorkshire
If people live in one of the affected areas they must not host people they do not live with in their home or garden, unless they are in their support bubble.
You also must not meet people you do not live with in their home or garden, whether inside or outside of the affected area, unless they are in your support bubble, according to the Government website.
A support bubble is where a household with one adult joins with another household. Households within a bubble can still visit each other, stay overnight, and visit public places together.
Blackburn, Oldham and Pendle
As with the above, there is a ban on two households mixing indoors or in a garden.
People should not visit friends or family in care homes, other than in exceptional circumstances.
And in specific areas with additional restrictions, people should not socialise with people they do not live with at indoor public venues or outdoor venues such as parks.
People should not have visitors to their homes or socialise with people they do not live with in other indoor public venues such as pubs, restaurants, cafes, shops, places of worship, community centres, leisure and entertainment venues, or visitor attractions.sonos sonos One (Gen 2) - Voice Controlled Smart Speaker with Amazon Alexa Built-in - Black read more
They also should not visit friends or family in care homes, other than in exceptional circumstances.
There are no local lockdown measures in Northern Ireland so far.
Official data shows the surge of new cases over July and August has been driven by those in their teens and 20s while cases in older generations continue to decline.
British hospital admissions have remained stable with just one in 100,000 people currently needing medical care for Covid-19 infection, which further supports people aren't getting seriously sick with the disease.
It follows Mr Hancock telling MPs in the House of Commons that 'just because we've come through one peak, it does not mean we cannot see another one coming'.
Several locations in the UK have had to impose tighter Covid-19 restrictions to try and curb transmission, with pubs in Bolton the first in England to be ordered back into into lockdown.
The Department of Health's update of 30 Covid-19 deaths on Tuesday covers all settings, including hospitals, care homes and private homes.
Scotland recorded three Covid-19 deaths across all