The latest figure is 100 more tha were confirmed the previos day, making both the highest since May 8. There were 3,638 new coronavirus infections in England, 350 in Scotland, 222 in Northern Ireland and 212 in Wales. An additional 27 people have also died from COVID-19, taking the death toll up to 41,759.
Health officials and experts have warned more infections are likely to be recorded now as the number of coronavirus tests available has grown dramatically since the pandemic began.
The latest terrifying data comes after a leading scientist warned the Government needs to act "sooner rather than later" if they are to prevent a new surge in coronavirus cases leading to several more deaths.
Professor Neil Ferguson - whose modelling led the Government to order the lockdown in March - warned the UK is facing a "perfect storm" with lockdown restrictions eased throughout the summer.
Boris Johnson is currently considering new restrictions across England, with recent figures showibng new infections are doubling every week.
Daily coronavirus infections have again surged to a four-month high
Ministers are reportedly looking at a temporary two-week "circuit break" in an attempt to curb infections.
This could see pubs and restaurants face closure or have a 10pm curfew imposed on them.
Socialising between households could be banned.
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12.34am update: Britons at risk of £10,000 fine for refusing to self-isolate
People in England who ignore orders to self-isolate could face fines of up to £10,000, the Government has revealed.
The legal requirement says that people have to self-isolate if they test positive for coronavirus or have been in close contact with someone who has, from 28 September.
The new measures will issue penalties to employers who punish staff members who have been told to self-isolate.
It also includes one-off payments for those on lower incomes.
Manon Dark takes over live reporting from Paul Withers.
8.58pm update: Met condemn 'unacceptable' outbreaks of hostility at coronavirus protest
Police have lashed out at the "unacceptable" outbreaks of "hostility and violence" towards officers at the anti-vax, anti-lockdown protest in central London, which saw 32 people arrested.
Hundreds of of protestors gathered in Trafalgar Square for a "Resist And Act For Freedom" rally, including some bearing 5G conspiracy placards and signs declaring coronavirus a "hoax".
Several officers, including some on horseback and in riot gear, were forced back by crowds, with some throwing missiles.
Scotland Yard said two officers suffered minor injuries.
Trafalgar Square was cleared of protesters after 5pm, with 32 people arrested for offences including violent disorder, public order and assault on an emergency worker, as well under Covid regulations.
Superintendent Emma Richards said: "We remain in the middle of a public health crisis, and by gathering in large numbers - such as today's protest - puts others at risk. We advised those in attendance to leave but many refused to do so.
"The amount of hostility shown towards officers, who were simply there to keep people safe, is unacceptable. More than 30 people were arrested and they remain in custody."
The Met Police battled to contain protesters at a demonstration in London
8.04pm update: Coronavirus and Brexit 'have made Irish unity part of every day conversation'
Sinn Fein's President has said COVID-19 and Brexit have made Irish unity part of "every day conversation".
Mary-Lou McDonald said in an online message: "Brexit and Covid-19 have made Irish unity part of every day conversation.
"Growing our economy, protecting our health service, strengthening our agriculture require an all Ireland approach.
"So now is the time to progress this journey together."
7.20pm update: Ireland reports 274 news coronavirus cases - 166 in Dublin
The country's National Public Health Emergency Team has announced a further 274 confirmed coronavirus.
From this, 166 were in Dublin, 21 in Cork, 19 in Donegal, seven in Kildare, seven in Offaly, six in Waterford, six in Wicklow, five in Louth, five in Limerick and five in Meath.
The remaining 27 cases were located across 12 counties.
No further deaths have been reported, meaning Ireland's toll from COVID-19 remains at 1,792.
6.52pm update: Met arrest 32 people during anti-lockdown demonstration
The Metropolitan Police have said they made 32 arrests during the anti-lockdown demonstration that took place in Trafalgar Square earlier today.
The force added the area has now been cleared.
Boris Johnson is considering new coronavirus measures for England
6.15pm update: Turkish coronavirus cases suge past 300,000
The total number of confirmed coronavirus cases in Turkey has gone above 300,000, as authorities desperately try to contain a resurrgence in the outbreak.
The country's health ministry said there had been 1,538 new cases in the last 24 hours, taking the total to 301,348. #
The death toll increased by 68 to a total of 7,445.
On Friday, President Tayyip Erdogan said the Government needs to increase measures to control the rise in new cases.
5.47pm update: Doctors call fror stronger measures to avoid another national lockdown
Doctors are urging the Government to introduce strong measure in Egngland to drive down coronavirus case numbers and avoid a second national lockdown.
The British Medical Association (BMA) warned unless people rigorously follow social distancing and infection control measures, or there is better enforecement, infection rates will continue to rise, and the NHS will "once again be crippled" as it struggles to cope with a surging number of patients.
The BMA wants the Government to econsider the "rule of six", which bans social gatherings of more than six people.
The association warned the measure makes it possible for members of six households to meet indoors, potentially many times over the course of one day.
It also wants the government to reverse its stance on getting workers back to the office by encouraging the public to work from home, meaning less contact between people, including on public transport.
Dr Chaand Nagpaul, chairman of the BMA, said: "It is vital to reduce avoidable mixing of people at a time when the infection is spreading without the testing capacity to identify those with the infection.
"This requires revisiting the rule of six which allows members of six different household to meet indoors compared to a maximum of two previously, and reversing the encouragement to travel and return to work for those able to work remotely."
He added: "We need to know the criteria for when different restrictions will be introduced, and local public health specialists need to have the autonomy to act in the best interests of their own towns and cities."
4.45pm update: UK coronavirus surge to four-month high
The UK has reported the number of people testing positive for coronavirus has jumped by 4,422 over the past 24 hours - the highest in over four months.
This is 100 more than were confirmed on Friday, meaning both are the highest since May 8.
An additional 27 people have died from COVID-19, taking the death toll up to 41,759.
4.25pm update: Scotland announces three more coronavirus deaths
A further three people have died from coronavirus in Scotland, increasing the total death toll from COVID-19 in the country to 2,505.
Confirmed cases have increased bby 350 from the day before, with the number of people testing positive for coronavirus now standing at 24,126.
The latest figures come a day after Nicola Sturgeon warned "hard but necessary" decisions may be needed in the coming days to prevent another lockdown in Scotland.
The First Minister also warned coronavirus "could get out of our grip again" as Scotland faces the risk of "exponential growth" of COVID-19.
The Met Police have issued a warning to protesters in Trafalgar Square
3.20pm update: Met orders protesters to disperse or face arrest
The force said those attending an anti-vaccination, anti-lockdown demonstration in Trafalgar Square are "putting themselves and others at risk" and some had been "hostile" and "violent" towards officers who had attempted to "explain, engage and encourage them to leave".
A statement said: "This, coupled with pockets of hostility and outbreaks of violence towards officers, means we will now be taking enforcement action to disperse those who remain in the area. Those who remain may get arrested.
"It is important to remember that we are still in the middle of a global pandemic, and the changes have been introduced to help control the spread of the virus, keep everybody safe and save lives.
"We encourage those in attendance to leave the area immediately."
3pm update: London CHAOS: Thousands at Trafalgar Square in FURIOUS lockdown protest - police on scene
Anti-lockdown protesters have scruffled with police today in Trafalgar square amid fury over a possible return to lockdown as the nation braces itself for a second wave of coronavirus.
Scuffles have broken out between demonstrators and police at a rally in Trafalgar Square organised by opponents of coronavirus lockdown measures.
Metropolitan Police officers moved in on the protesters as they congregated near Nelson's column on Saturday.
The protesters formed human blockades opposite the officers to stop them from making arrests.
One supporter of the protests tweeted: "Only 500 expected at today's anti-lockdown protest in Trafalgar Square, London, one or two more!
Sturgeon calls for Cobra meeting as Scotland’s latest coronavirus figures released
Paul Withers taking over live reporting from Katie Harris.
2.50pm update: England’s coronavirus hospital death toll up 16
A further 16 people who tested positive for coronavirus have died in hospital in England, bringing the total number to 29,735, NHS England said on Saturday.
2.40pm update: Ireland can reduce coronavirus number again - Taoiseach
Irish premier Micheal Martin has insisted that the country can bring coronavirus numbers down again.
The Taoiseach was speaking as Dublin entered three weeks of tighter restrictions to combat a surge in cases.
Protesters have gathered for a demonstration against coronavirus lockdown restrictions in Trafalgar Square
2.35pm update: Northern Ireland records 222 new cases
There have been a further 222 coronavirus cases in Northern Ireland.
This brings the total number to 9,165, including 913 in the last seven days.
2.20pm update: Sturgeon calls for Cobra meeting as Scotland’s latest coronavirus figures released
Three more people have died with coronavirus in Scotland, according to the latest figures, taking the overall toll to 2,505.
The number of confirmed cases has increased by 350 to 24,126.
In a tweet, First Minister Nicola Sturgeon warned coronavirus is on the rise.
She said: “Given serious situation across UK, I have also asked again that a 4 nations COBR meeting takes place over next 48 hours.
“While each of the 4 UK nations will reach our own decisions - rightly and properly - it makes sense to seek as much co-ordination and alignment as possible.”
The Prime Minister has insisted a second lockdown is the "last thing anybody wants" but admitted the current measures would need to be kept "under review"
2.05pm update: Anti-lockdown protest in London
Protesters have gathered for a demonstration against coronavirus lockdown restrictions in Trafalgar Square.
Crowds attended the Resist And Act For Freedom rally.
One carried a sign calling for the Government's Sage scientific advisers to be sacked, while another's declared coronavirus a "hoax".
1.45pm update: Iran’s death toll passes 24,000
Iran's coronavirus death toll has risen by 166 to 24,118.
The number of confirmed cases jumped by 2,845 to 419,043.
12.55pm update: 'Twindemic' poses huge threat as UK 'seeing second wave'
With the nation bracing itself for a second wave of COVID-19, the UK is at risk from a deadly double whammy this winter, a US-based expert has warned.
Professor Amesh Adalja, Senior Scholar at the Johns Hopkins Center for Health Security in Baltimore, said the situation was certain to be made more difficult by seasonal flu - suggesting the world was facing, what he called, a "twindemic".
Prof Adalja told Express.co.uk: "Influenza and COVID-19 circulating at the same time is a concern because both of these infections will compete for the same hospital resources, personal protective equipment, and even diagnostic test reagents.
"This is why it is essential, because we have an effective flu vaccine, to increase vaccination rates against influenza so that we have room to deal with COVID-19 patients if transmission accelerates, as expected, in the fall and winter."
12.10pm update: Should there be a two-week lockdown to halt COVID spike?
Boris Johnson could bring in a two-week lockdown to combat soaring coronavirus cases - but do you think there should be another shutdown?
Express.co.uk readers can vote in our poll on whether they agree with another national lockdown.
Our poll comes as ministers are thought to be considering a two-week "circuit break" in a bid to slow transmission of the virus.
The Prime Minister has insisted a second lockdown is the "last thing anybody wants" but admitted the current measures would need to be kept "under review".
The PM pictured during a visit to the Vaccines Manufacturing Innovation Centre construction site near Oxford on Friday
11.30am update: Poland confirms record daily increase in infections
Poland has reported 1,002 new coronavirus cases - the highest daily increase since the pandemic began.
10.50am update: Indonesia reports biggest daily rise in coronavirus cases
Indonesia has recorded its biggest daily rise in coronavirus infections, with 4,168 new cases.
The overall total number of infections now stands at 240,687.
The country’s death toll has jumped by 112 to 9,448.
Meanwhile, the Philippines has confirmed 3,962 new cases and 100 deaths.
Russia has confirmed 6,065 further coronavirus cases
10am update: Russia reports 6,065 new coronavirus cases
Russia has confirmed 6,065 further coronavirus cases - the first time the daily tally has been higher than 6,000 in two months.
The new infections take the country’s overall total since the start of the outbreak to 1,097,251.
Russia’s death toll has increased by 144 to 19,339.
9.10am update: Professor warns new coronavirus restrictions needed ‘sooner rather than later’
Professor Neil Ferguson - whose modelling led to the Government ordering the nationwide lockdown in March - told the BBC Radio 4 Today programme: "Right now we are at about the levels of infection we were seeing in this country in late February.
"If we leave it another two to four weeks we will be back at levels we were seeing more like mid-March. That's clearly going to cause deaths because people will be hospitalised.
"I think some additional measures are likely to be needed sooner rather than later.
"We have in some sense a perfect storm right now of people, as they have been told to, getting back to normal - schools reopening, a surge in cases so therefore the testing system is under strain.
"So unfortunately we do have to roll the relaxation of measures back a little bit and get contacts down in the population."
Labour deputy leader Angela Rayner has urged the Prime Minister to call a Cobra meeting
8.40pm update: Labour deputy leader urges PM to call Cobra meeting
Angela Rayner told the BBC Radio 4 Today programme: "We are deeply concerned with the sharp rise in infection rates.
“What we have seen over the last six months is the Government still can't get the basics right.
"The Prime Minister has to convene a Cobra meeting this weekend.
“He has to look at the science and the evidence and he has to make sure the measures are in place and a clear communications strategy on that so people can do the right thing.
"It has been absolutely shocking to see how monumentally they have failed at the testing, tracing, tracking system that they put in place."
8am update: India’s parliament session likely to be cut short
India's parliament session is likely to be cut short after 30 lawmakers tested positive for coronavirus.
The Indian parliament met for the first time in six months on September 14 and was due to continue until October 1 but it could be reduced by a week.
An official said: "Since the commencement of the session the number of positive cases have gone up so the government is thinking of cutting short the session.”
UK coronavirus map as of September 18
7.30am update: Victoria records lowest number of cases since June
The Australian state of Victoria has reported its lowest daily increase in infections in three months.
The state, which has been at the centre of Australia’s coronavirus outbreak, confirmed 21 new cases in the past 24 hours and seven further deaths.
Overall, the country has recorded just under 26,900 infections and the death toll stands at 844.
7.15am update: Minister says it would be "wonderful" to have coronavirus-free care homes by September 2021
Care minister Helen Whately has written a letter to the heads of local authorities, care home providers and public health and adult social care directors expressing her hopes that coronavirus will be eradicated from care homes by September 2021.
Ms Whately said: "This time next year, it would be wonderful to achieve our objective of Covid-free care homes, resilient communities and a health and care workforce still able to give their very best."
The letter was published alongside the Government's adult social care winter action plan on Friday evening.