People who seriously flout new lockdown restrictions in England will face steep fines, Justice Secretary Robert Buckland has warned.
Under the rules, people have been told to stay at home and non-essential shops, pubs and gyms ordered to close.
Households are also banned from mixing indoors or in private gardens, unless in a support bubble.
Currently there is a £200 fine for each breach which doubles on every offence up to a maximum of £6,400.
And organisers of large gatherings face a £10,000 fine.
Speaking on BBC Breakfast, Mr Buckland said law enforcement would continue its approach of “policing by consent” to encourage the public to comply with the four-week lockdown.
But he added that police would respond to “egregious breaches” and then the law would “take its course”.
He said: “Where a more intense intervention is needed then the police will be involved and of course the fine structure is still in force.”
The National Police Chiefs Council has also warned the most serious offenders will face fines.
Mr Buckland said he supported the police clamping down on the “tiny minority” of people who are not willing to obey the lockdown.
“I think the message has to go out very clearly that this will only work if we all play our part,” he told BBC Radio 4’s Today programme.
Meanwhile, the Bank of England is to pump an extra £150bn into the economy amid a resurgence of Covid-19 cases. It has left interest rates on hold at a record low of 0.1%.
The new lockdown, which came into effect at midnight, will “expire automatically” on 2 December, according to Prime Minister Boris Johnson.
But the head of the Confederation of British Industry (CBI) has called for an urgent extension of the government’s furlough scheme – which pays 80% of workers’ wages – until the spring to prevent job losses.
Chancellor Rishi Sunak is set to make a statement in the House of Commons later outlining what economic support will be available to businesses and jobs during the lockdown.
He is expected to confirm employees on furlough will receive 80% of their salaries if their workplaces have been shut down, and is likely to guarantee furlough funding for Scotland, Wales and Northern Ireland if the devolved administrations bring in their own lockdowns.
Newspaper reports have suggested the chancellor will announce an extensionof furlough beyond December.
On Wednesday, MPs backed the lockdown, which aims to combat a surge in coronavirus cases – and replaces the three tiers of regional restrictions that were previously in place across England.
There will be another vote on the next steps needed to tackle the virus before the four-week lockdown ends.
Mr Johnson told MPs a second lockdown was “not something any of us wanted to do” but insisted the restrictions represented “the best and safest path for our country”.
It came as the UK recorded a further 492 coronavirus deaths – the highest daily figure since 19 May – and 25,177 confirmed cases.
Under the new restrictions, people should stay at home except for specific reasons including education and work (if it cannot be done from home).
All non-essential retailers, leisure and entertainment venues must shut, with pubs and restaurants told to close except for takeaways.
Martin Hewitt, chairman of the National Police Chiefs Council, warned that those responsible for the most “egregious” breaches of the rules would face stiff fines.
He said: “Every one of us has a responsibility to understand what the regulations are and abide by those regulations”, adding that people who flouted them would be “breaking the law and endangering people’s lives”.
Shoppers in England flocked to stores to make last-minute purchases on Wednesday, with some retailers extending their opening hours to cope with the huge demand.
Unlike the first lockdown in March, schools, universities, and nurseries will remain open, and people will be able to meet another person who they do not live with in an outdoor public place such as a park or beach.
The rules says people cannot mix with anyone they do not live with indoors or in private gardens.
In other developments:
- New guidance issued by the Department for Education says adults and children aged 11 and above should wear a face covering when moving around the school, outside of classrooms or activity rooms, “where social distancing cannot easily be maintained”
- Clinically extremely vulnerable people in England are being strongly advised not to go to work outside their homes during lockdown from Thursday
- Care homes must provide a Covid-secure environment – such as floor-to-ceiling screens, window visits or visiting pods – to allow families to see loved ones during the lockdown
- Doctors have warned patients not to delay in seeking medical advice should they need it during the next month
- On Wednesday, the NHS in England was placed on its highest alert level, as bosses said they were seriously concerned about the added pressure on the health service