Watch: Targeted testing to start
People without COVID-19 symptoms will be targeted for coronavirus testing across England, as the vaccination push ramps up this week.
Quick turnaround tests will be given to every local authority in England with the aim of prioritising key workers unable to work from home during the lockdown.
Lateral flow tests, which can return results in as little as 30 minutes, are at the centre of the community testing programme.
It comes as the pandemic gathers pace in the UK and fears grow that current lockdown restrictions are being ignored by the general public.
England's chief medical officer Chris Whitty has warned that the NHS faces the "most dangerous situation" in living memory and once again pleaded with people to stay home.
"If the virus continues on this trajectory, hospitals will be in real difficulties, and soon," he wrote in the Sunday Times.
The number of patients with COVID-19 in hospital is at a record high in England, while the official coronavirus death toll for the UK passed 80,000 on Saturday and lab-confirmed cases hit more than three million.
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Medics and experts have warned things are likely to get worse still, with the full impact of Christmas not yet evident. One medic told Sky News the NHS is "breaking in front of us".
Other experts have branded the current lockdown measures not strict enough, in the face of the more transmissible variant, and suggested compliance is waning.
Sky News analysis shows that people are moving about more during this lockdown than the first, suggesting people have become used to bending the rules.
Meanwhile, Home Secretary Priti Patel has warned of a crackdown on lockdown breaches.
Health Secretary Matt Hancock said targeted asymptomatic testing followed by isolation is "highly effective in breaking chains of transmission".
He said the government was asking employers to "work with us to scale up workforce testing" as it was announced local authorities will be encouraged to target testing towards those who cannot work from home.
He said: "Lateral flow tests have already been hugely successful in finding positive cases quickly - and every positive case found is helping to stop the spread - so I encourage employers and workers to take this offer up.
"We must all do all we can to stop the spread of COVID, right now."
On Friday, the government revealed a new TV campaign urging people to behave like they are infected with coronavirus and to stay at home.
The government is stepping up the vaccination drive in a bid to meet its target of vaccinating 14 million vulnerable people in the UK by mid-February.
Letters have been sent to the 500,000 over-80s who live up to a 45-minute drive from one of seven new regional vaccination centres in England, inviting them to book an appointment.
Separately, Buckingham Palace revealed the Queen and Duke of Edinburgh received their vaccinations from a royal household doctor on Saturday.
The Oxford/AstraZeneca vaccine will be available in more than 1,000 locations in Scotland from Monday; while, Wales' First Minister Mark Drakeford tweeted that vaccinations there are "gathering momentum".
He has faced criticism about the speed of the rollout which, as of Friday, had seen just 1.6% of the Welsh population jabbed, compared to 1.9% in England and 2.1% in both Scotland and Northern Ireland.
The national rollout will be boosted further by the spring when the recently-approved Moderna vaccine becomes available.