Video report by ITV News Political Correspondent Daniel Hewitt
Blantant Covid-19 rule-breakers have been warned they should expect to be fined, with police stepping up their enforcement of lockdown restrictions.
National Police Chiefs' Council chairman Martin Hewitt, speaking at a Downing Street press conference, said officers will not "waste time" trying to reason with people who have "no regard" for the safety of others.
He said its been "disappointing" to see so many rule breaches, with almost 45,000 fines having already been handed out during the pandemic.
The police warning came as the UK recorded its second highest daily death toll since the pandemic began.
There have been 1,243 deaths reported in the past 24 hours, which takes the total death toll up to 83,203, and 45,533 new cases have been reported.
Mr Hewitt pointed to a number of recent examples of "irresponsible behaviour" - including a boat party in Hertfordshire with more than 40 people, and a minibus full of people from different households travelling from Cheltenham into Wales for a walk.
He attacked those organising large gatherings, describing them as "dangerous, selfish and totally irresponsible".
"Organisers will be fined," he said, "but so too will the people who choose to attend. "
He went on: "Not wearing a face covering on a bus or a train is dangerous. It risks the lives of other travellers including those critical workers who must continue to use public transport to do their important work. So on those systems, unless you are exempt, you can expect a fine."
Home Secretary Priti Patel insisted coronavirus regulations are clear, despite ambiguity around a number of the rules, including one which states people can only exercise in their local area.
With no exact definition of local, the rule has caused confusion; two women were incorrectly fined last for travelling five miles to exercise.
Derbyshire police has since apologised and rescinded the fine but the issue has highlighted how the rules can be interpreted.
Days later Boris Johnson travelled seven miles from his home for a bike ride in east London, a journey Downing Street has insisted was lawful.
Asked why the regulations were not as tough as the first lockdown despite the tough situation faced by the NHS, she said "the rules are clear, the rules are firm in terms of staying at home".
She added: "We are meant to stay at home and only leave home for a very, very limited number of reasons."
Outdoor recreation is permitted, she said, "in a very, very restricted and limited way, staying local".
She added that police had set out "the type of egregious breaches that we will clamp down on".
Mr Hewitt said defining exactly how far people can travel away from their home for exercise would be "challenging".
"I don't think we are in a position where we want to set a particular distance because how would - if a police officer stopped somebody - prove that a person is within or outside that distance."
Excess deaths (number of deaths above the average for the corresponding period in the previous five years) in homes in England and Wales between March 7, 2020 and January 1, 2021 are also at 40,114 - according to the Office for National Statistics (ONS).
In care homes, deaths have hit levels not seen since May. In the first week of January, 824 people died in care homes in England, according to Care Quality Commission records.
ONS data shows that 27.6% of all care home deaths in England and Wales can be attributed to Covid-19.
Southampton General Hospital is now treating 298 Covid patients - 44 of them are in intensive care.
And Covid patients in the Wolverhampton hospital ward, which is near capacity, are aged in their 20s upwards and the normal ICU capacity has increased by 200%.
Watch the press conference in full: