Boris Johnson warned tonight that draconian new coronavirus restrictions could be here for months - as he threatened even tougher action if the situation does not come under control.
Addressing the nation at a No10 press conference, the PM said the spike in infections seen over the past week left him no choice but to tighten lockdown across England for the first time since March.
'We must act,' he said.
And he warned that the 'rule of six' limit on how many people can socialise together will be in place for some time to come, after partying among the younger generation fuelled a sharp rise.
In a major setback for his ambition to get back to normal by Christmas, government sources have voiced gloom about a 'difficult six months' to come. One official cautioned that it was not a scenario of ‘a couple of weeks and we’re back to where we were’, saying the R number was 'clearly above one'.
From Monday it will be illegal to assemble in groups of seven or more anywhere in England, whether indoors or out.
The limit - sparked by concern that partying young people are fuelling a flare-up - is a dramatic reduction on the maximum of 30 put in place on July 4. It will be enforced by police with £100 fines, doubling on each repeat offence up to £3,200.
Only schools, workplaces and a limited number of other locations will be exempt.
Pubs and restaurants will also be legally obliged to collect contact information. Before they were only asked to in government guidance.
Mr Johnson said he was 'sorry' that larger households would not be able to meet up, as they would be above the six-person threshold. 'But as your PM I must do what it takes to stop the spread of the virus.'
But Health Secretary Matt Hancock made clear this morning that the government is ready to step up the restrictions again if necessary. He praised action taken to slash socialising in Belgium, where a curfew was imposed and appears to have helped stabilise cases.
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 PM told the House of Commons that the spike in infections seen over the past week left him no choice but to act
Slides presented at the press conference tonight show that younger people are driving the increase in Covid cases
Boris Johnson looked to be feeling the heat after a run this morning (left), as he struggles to control a flare-up in Covid cases. Matt Hancock (right) praised the action taken in Belgium, which imposed a curfew
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.
Bars and restaurants in Bolton, which has the highest rates in the UK, have already been ordered to shut by 10pm and only serve takeaway.
However, Mr Hancock also insisted that despite the tough steps it was still right for people to return to offices. He said workplaces were 'Covid secure' and evidence showed almost all transmission happened in social settings.
But revealing the tightening overnight, 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.
'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.'
Mr Hancock told Sky News that the restrictions were 'absolutely vital to protect life'. 'We've seen the increase in the number of cases sadly in the last few days. We've seen that across Europe there's a second wave that many countries have experienced.
'Some of those countries have then got that second wave under control. If you look at what's happened in Belgium they saw an increase and then they've brought it down, whereas in France and Spain that just hasn't happened.'
The England-wide crackdown was sparked after cases topped 2,000 three days running - taking the UK well over the threshold at which it considers imposing quarantine measures on other countries.
In another worrying sign the number of deaths announced yesterday hit 30, the highest in six weeks.
Behind the scenes officials have become increasingly concerned at the direction of travel, with fears that the UK could follow the path of places like France, where infections have risen far more and deaths have started to follow.
Mr Johnson had a conference call with police last week during which he was urged to simplify the rules so enforcement was easier.
The Health Secretary said the Government was moving to 'simplify' the rules around social gatherings by limiting groups to six either indoors or outdoors.
Speaking to Times Radio, Mr Hancock said: 'It will be much easier for the police to enforce because the previous rules where you had two households it was much harder to work out what was and wasn't OK.'
Fines for those who breach the rules will range from £100 to £3,200, the Health Secretary said, although there will be exceptions for events such as weddings, funerals and Christenings.
'We have got to bring in clear, stricter rules this autumn unfortunately to stop the spread of the virus,' he said.
'One of the things we heard back including from the police directly was that we needed a simpler set of rules that are very straightforward, (that) everybody can understand, and we will be publishing those rules very clearly and then enforcing against them.'
Mr Hancock has refused to rule out a second lockdown, despite assurances by the Prime Minister.
Speaking to LBC, Mr Hancock said: 'Our goal is to avoid having to do anything more drastic by people following the rules.'
But he would not rule out a return to lockdown, saying: 'I wouldn't make a vow like that.
'You wouldn't expect me to – I am the Health Secretary in the middle of a pandemic where we are trying to keep the country safe.'
But he added he 'hoped' lockdown could be avoided, saying: 'The number of cases is largely driven by people socialising.'
Pressed whether the government was still aiming for a return towards normality by Christmas, he said: 'I really hope we can turn this around before Christmas.'
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.
The data presented at the press conference show that cases are still low relative to some other European countries
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.
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'.
September 2: Bolton and Trafford were due to be taken out of lockdown, but the idea is ditched at the last minute after an appeal from local leaders who warned cases were too high.
Boris Johnson tells MPs of his determination to get Britons back in the office, revealing that part-time season tickets could be introduced.
September 3: Matt Hancock says rapid new saliva tests for Covid could mean the country is back to normal by Christmas.
Portugal and Greece are kept off England's quarantine 'red' list for arrivals, despite restrictions being imposed by both Wales and Scotland.
September 4: Cases hit 1,940 in a day, the highest level since May. Boris Johnson rejects calls for testing at airports, saying it would only give a 'false sense of security'.
September 6: Case numbers spike again to 2,988, the most recorded since May 27. However, experts point out that hospitalisations and deaths remain at a very low level.
September 7: New infections dip slightly but are still more than double the Joint Biosecurity Centre's safe level, at 2,420.
Grant Shapps partially follows the example of Scotland and Wales by adding seven Greek islands to the quarantine list.
Nicola Sturgeon announces that lockdown will not be easing further in Scotland, as had been schedule.
September 8: Mr Hancock announces that a draconian lockdown is being imposed in Bolton, as it has the highest rate in the UK. Pubs and restaurants are ordered to shut by 10pm and people cannot socialise outside their household.
Across the UK, daily infections are again above 2,000.
The PM tells Cabinet that in other countries a rise in cases has been followed by more deaths, and they are taking the situation 'seriously'.
September 9: Mr Johnson announces a legal ban on gatherings of more than six people, enforced by fines. Mr Hancock hints that Belgium-style curfews could be considered next.
He stressed that social distancing was the first line of defence and said he was concerned about the situation in France and Spain.
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 yesterday - 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 authorities in Belgium became increasingly alarmed after seeing a steady rise in coronavirus cases during July.
But the worrying trend appears to have been arrested by tougher restrictions - including an edict that night venues stop serving alcohol by 10pm.
The city of Antwerp, the worst hit in the country, brought in a curfew at the end of July that every member of the public must be home between 11.30am and 6am.
In mid-August the curfew period was eased to 1.30am to 5am.
There is a limit of four people sitting at a table together in restaurants, unless they are from the same household.
Plans to reopen nightclubs and major events have also been put on hold.
In Brussels, wearing a face mask became compulsory in all public areas on 12 August.
Police have also been enforcing the rules more strictly.
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.
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.
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 oldsonos sonos One (Gen 2) - Voice Controlled Smart Speaker with Amazon Alexa Built-in - Black read more
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
Scotland recorded three Covid-19 deaths across all settings earlier in the day - the highest since June 30.
It comes after several weeks with barely any deaths and after First Minister Nicola Sturgeon warned this week hospitalisations may also be on the up.