Britain's Covid cases rise by a THIRD in a week with 20,263 people testing positive as the country records 189 more deaths - a 23% increase on last Monday

Britain's daily coronavirus cases have risen by more than a third compared to last Monday, after 20,263 people tested positive today.

Official figures also revealed 232 people have died after contracting the virus - in a 22.8 per cent spike on the 189 deaths seen on this day last week.

Today's case total is the highest Monday figure since November 9, when 21,350 cases were reported in the early days of the country's second national lockdown. 

Monday's 20,263 cases is 37.6 per cent bigger than the 14,718 recorded on December 7.

Today's figures come as 10million people in the South East are thrust into Tier 3 shut down with just 30 hours' notice following a surge in Covid infections in the region. 

The Health Secretary told the Commons that the tough new rules will come into effect in London just after midnight on Wednesday morning, sparking fury that he is sending thousands of businesses to the wall.

It comes as:

Britain's daily coronavirus cases have soared by more than a third compared to last Monday, after 20,263 people tested positive today

Official figures released today also revealed 232 people have died after contracting the virus - in a 22.8 per cent spike on the 189 deaths seen last Monday

Large areas of Hertfordshire and Essex will also go into Tier 3 after seeing 'sharp and exponential' growth. 

It means around 60 per cent of the population of England will be under the highest level of restrictions - although extraordinarily No10 has insisted that all the curbs will still be relaxed on December 23 as part of the Christmas 'bubbles' plan. 

Leading scientists have urged families to exercise caution this festive season and avoid gatherings that could 'risk infecting the vulnerable and elderly people we love' - amid fears that the country could see a third wave.  

Under the Government's plans for a more-normal festive season, families are able to form a 'bubble' with two other households between December 23 and 27.

Addressing the nation at a televised press conference, Mr Hancock added: 'We know from experience that the best thing to do in the face of this virus is to act fast, not to wait to see its growth continue - and we do not rule out further action'

But NHS executive Chris Hopson has urged Mr Johnson to exercise 'extreme caution' before putting any region into a lower tier as any relaxing of rules 'will trigger a third wave'. 

Risk of catching coronavirus from a family member you live with is just 17%, study finds 

The risk of catchingncoronavirus from a family member is less than one in five, a new study suggests.

In a meta-analysis, researchers found that just 16.6 percent of all people with Covid-19 passed it on to members of their family.

More than one in three people spread the virus to their spouses. 

What's more, when the infected person did not have symptoms such as cough, fever or shortness of breath, the transmission rate was just 0.7 percent.

The team, from the University of Florida, says the results show that, because people with suspected or confirmed cases are told to isolate at home, people should consider wearing mask around family members who may have the virus.

For the analysis, published in JAMA Network Open, the team looked at 54 relevant studies with more 77,000 participants reporting household secondary transmission.

Researchers looked at multiple factors including adult or child contact, number of contacts and whether or not the ill person was symptomatic.

Results showed that that 16.6 percent of coronavirus patients spread the diseased to members of their household.

The rate was higher if the person had traditional symptoms such as cough, fever and shortness of breath, with 18 percent spreading to household members.

However, if the infected individual was asymptomatic, they spread it to just 0.7 percent of household contact.

Boris Johnson yesterday admitted in a virtual fund-raising event for Conservative party members that people needed to be cautious over the festive period.

In messages revealed yesterday, he said: 'My message to everybody is we do have this period of relaxation of measures at Christmas, but I really urge people to think hard about how you choose to enjoy that relaxation. 

'I really would urge people to err on the side of caution rather than, I'm afraid, have a big blow-out with multiple households.

'I know the rules say three households, but there is ample scope alas for further increases in this disease during tough winter months.'

Addressing the nation at a televised press conference today, Health Secretary Matt Hancock said: 'We know from experience that the best thing to do in the face of this virus is to act fast, not to wait to see its growth continue - and we do not rule out further action.' 

But he faced down questions over the wisdom of relaxing some restrictions on family gatherings at Christmas.

In response he said: 'If you want to see elderly relatives at Christmas the best thing to do is be extremely careful now about who you see.'

Professor Chris Whitty reiterated that people need to be cautious at Christmas and should not meet just because they can.

'The point of this (relaxation of rules) is for, under certain circumstances, families who wish to, to get together, but they really have to be very, very careful.

'And in particular, incredibly careful if they're around people who are vulnerable, who are at very high risk of this virus.'

In another bombshell announcement Mr Hancock said that scientists had identified a 'new variant' of the virus that appeared to be influencing the spread in the south of England.

He said initial evidence was that it is growing much faster than the previous strains, although he tried to cool fears by stressing that it did not seem to be more deadly, and there was low risk that it will not respond to vaccines. 

'We have identified a new variant of coronavirus, which may be associated with the fastest spread in the south-east of England,' Mr Hancock told MPs this afternoon.

'Initial analysis suggests that this variant is growing faster than the existing variants. We've currently identified over 1,000 cases with this variant, predominantly in the south of England, although cases have been identified in nearly 60 different local authority areas, and numbers are increasing rapidly.'

Mr Hancock said the strain had also been identified in other countries and the World Health Organisation had been notified, with tests still being carried out at the government's Porton Down lab. 

Greenwich's council leader Danny Thorpe has told all schools in the south-east London borough to close from Monday evening as he warned its Covid-19 situation was 'escalating extremely quickly'. The infection rate per 100,000 people in the capital stood at 191.8 on December 6, up from 158.1 the previous week. Pictured: London infection rates by borough week to December 6

The Tier 3 move drew a furious reaction from local MPs and firms who warned it will devastate businesses. London mayoral candidate Shaun Bailey branded it a 'mistake' and said individual boroughs should be treated differently. Pubs, restaurants and culture venues will be closed, while shoppers from Tier 2 zones will be barred from shopping in major retail hubs like Oxford Street. 

West End theatres are also readying themselves to close after tomorrow night's performances. 

Meanwhile there is anxiety that Kent, already in Tier 3, could face a further tightening of restrictions with a surge in cases that has yet to fall.

In an apparent attempt to assuage anger, Mr Hancock indicated that the next review will be on December 23 - rather than December 30 as had been expected. 

However, in a grim statement to the House on the epidemiological situation he said: 'Initial analysis suggests that this variant is growing faster than the existing variants.

'We've currently identified over 1,000 cases with this variant predominantly in the South of England although cases have been identified in nearly 60 different local authority areas.

'And numbers are increasing rapidly.'  

The Government agreed to review the tier levels every two weeks at the latest after they were introduced on December 2, in order to pass the legislation needed in the face of a backbench rebellion.  

But the decision was brought forward from Wednesday to today because of the spike in numbers, with a key cabinet committee having met this morning.