Members of the public wearing face masks queue at a shop in southwest London on Saturday.
London - From Sept 28, people will be legally obliged to self-isolate if they test positive or are told to by the National Health Service tracing programme, says PM Johnson
People in England who refuse to self-isolate to stop the spread of coronavirus could face fines of up to £10,000 ($13,000, 11,000 euros) under tough new regulations announced on Saturday to tackle a surge in cases.
Prime Minister Boris Johnson said this week that Britain was seeing a second wave of Covid-19, and introduced new restrictions for millions of people across northwest, northern and central England.
In a further measure announced late on Saturday, he said that from September 28 people will be legally obliged to self-isolate if they test positive or are told to by the National Health Service (NHS) tracing programme.
"The best way we can fight this virus is by everyone following the rules and self-isolating if they're at risk of passing on coronavirus," Johnson said in a statement.
"And so nobody underestimates just how important this is, new regulations will mean you are legally obliged to do so if you have the virus or have been asked to do so by NHS Test and Trace."
Currently people who have symptoms or test positive are asked to self-isolate for 10 days. Those who live with someone who either has symptoms or tests positive must self-isolate for 14 days.
The new fines will start at Â£1,000 - in line with breaking quarantine after international travel - and rise to Â£10,000 for repeat offences and the worst breaches, including businesses that threaten self-isolating staff with redundancy, officials said.
In an incentive to get people to comply, those on low incomes will be able to claim an extra lump sum of Â£500 if they are unable to work from home during their isolation.
"While most people are doing their absolute level best to comply with the rules, I don't want to see a situation where people don't feel they are financially able to self-isolate," Johnson said.
Almost 42,000 people who have tested positive for Covid-19 have died in Britain, the worst death toll from the pandemic in Europe.
After a summer lull, cases are rising rapidly again and Johnson warned on Friday of a second wave.
"We are seeing it in France, in Spain, across Europe - it has been absolutely, I'm afraid, inevitable we were going to see it in this country," he said.
New rules limiting social gatherings to six people from different households came into effect this week, and local measures have been introduced across the country.
But Johnson has expressed his reluctance to introduce another nationwide lockdown and some of his Conservative lawmakers are increasingly vocal in condemning current restrictions.
In London on Saturday, anti-vaccine and anti-lockdown protesters clashed with police in Trafalgar Square. Police said 32 people were arrested.