People who break the coronavirus lockdown rules could be arrested or fined under new laws introduced on Thursday.
Those who ignore restrictions on movement could be fined £60, with the fine doubling after each offence, the Home Office warned.
Officers will have the power to enforce rules on staying at home and avoiding non-essential travel.
Some police forces have already set up roadblocks and checkpoints to ensure people are not making non-essential journeys.
Police will have powers to order members of the public to go home, leave an area and have powers to disperse a group.
They can also take steps to make sure parents are stopping their children from breaking the rules.
According to the guidance, the cost of initial fixed penalty notices will be cut to £30 if paid within 14 days and those who do not pay could be taken to court and risk facing costs for unlimited fines.
People who cough on emergency services could also be arrested under the sweeping new measures.
Dyfed Powys Police in Wales has already stopped some motorists and asking where they are going to make sure people do not make non-essential journeys.
Meanwhile, North Yorkshire Police have introduced checkpoints in the area. The checkpoints will be unannounced and could appear anywhere any time.
The UK’s largest police force, the Metropolitan Police, told ITV News it had no plans to implement roadside checkpoints.
The Home Office said: “If an individual continues to refuse to comply, they will be acting unlawfully, and the police may arrest them where deemed proportionate and necessary.
“However, in the first instance, the police will always apply their common sense and discretion.”
Home Secretary Priti Patel said: “The Prime Minister has been clear on what we need to do: stay at home to protect our NHS and save lives.
“All our frontline services really are the best of us and are doing an incredible job to stop this terrible virus from spreading.
“That’s why I’m giving the police these new enforcement powers, to protect the public and keep people safe.”
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