Thousands of school pupils across Britain will be tested for coronavirus as the number of new cases soar, Health Secretary Matt Hancock has announced.
Every student in the Covid-hit hotspots of Kent, Essex and London aged between 11 and 18 will undergo a test under the new scheme.
Mr Hancock said the campaign was being rolled out to stop coronavirus spreading to the wider community and stressed "targeted action" was required immediately.
"Cases are rising and in many areas, already high," Mr Hancock said at a news conference in Downing Street.
"We've decided to put in place an immediate plan for testing all secondary school aged children in the seven worst affected boroughs of London, in parts of Essex that border London and parts of Kent."
He said: “We know from experience that a sharp rise in cases in younger people can lead to a rise among more vulnerable age groups later.
“We need to do everything we can to stop the spread among school age children in London right now – we must not wait until the review, which will take place on December 16."
Today, the Office for National Statistics said the infection rate in Greater London is measuring 191.8 per 100,000 people, the highest rate in England.
London is at risk of being put into the highest category of coronavirus restrictions next week, meaning pubs and restaurants would be forced to shut.
London Mayor Sadiq Khan said the harshest Tier 3 coronavirus restrictions would be “catastrophic” for the capital.
Mr Hancock said he had spoken to the leaders of London’s councils and the London Mayor,
He added: “We want to keep schools open because that is both right for education and for public health.
“We are therefore surging mobile testing units and will be working with schools and local authorities to encourage these children and their families to get tested over the coming days.”
He said everyone in these groups should get tested irrespective of whether they have symptoms, adding that one in three Covid-19 cases are asymptomatic.
The weekly rate of new Covid-19 cases in the London borough of Havering has risen above 400 cases per 100,000 people.
Havering now has the eighth highest rate of any local authority area in England.
England’s chief medical officer Professor Chris Whitty told the briefing a third wave was “not inevitable” and said people must be “very, very sensible” over Christmas.
The latest data from the Government showed a further 516 people had died within 28 days of testing positive for Covid-19 as of Thursday.
In the press briefing, Mr Hancock said tens of thousands of people have been vaccinated with the jab from Pfzier/BioNTech in 73 UK hospital hubs.
He said GP-led sites would begin vaccinations next week, with jabs administered in some care homes by Christmas.
Meanwhile, experts have warned that it may be unwise for elderly people given the Covid-19 vaccine to hug their loved ones at Christmas.
As the NHS vaccination programme continues across the UK, scientists suggested people may only have partial immunity after a single dose of the vaccine and should wait until they are fully protected with a second dose.
Dr Simon Clarke, associate professor in cellular microbiology at the University of Reading, said: “The gift of the Pfizer vaccine rollout has not quite come in time for Christmas.
“It takes four weeks from the first jab of the Pfizer vaccine for someone to develop immunity to Covid-19.
“If someone is in receipt of the vaccine today, they will have to wait three weeks to get the second jab and then another week for immunity to develop.”