The UK has gone into full coronavirus lockdown, with the British public ordered to stay at home for up to six months.

People are allowed to leave their home only for essential work or exercise or to buy food or medicine.

All nonessential shops, premises, and places of worship are to be closed down, with weddings and baptisms banned.

The rules are to be enforced by the police with fines starting at £30 and rising to £1,000 for repeated infringement.

The announcement comes as the latest data suggests the UK is just two weeks behind the level of crisis seen in Italy.

The UK has so far recorded at least 6,650 coronavirus cases and 335 deaths.

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The UK public lockdown amid the coronavirus pandemic is set to last up to six months and be policed with fines beginning at £30 and rising to a maximum of £1,000 for anyone refusing to comply.

Prime Minister Boris Johnson announced the national lockdown in a statement to the nation Monday evening following a weekend in which the UK public had flocked to some public spaces in large numbers despite official guidance urging them to stay at home.

The ban, scheduled to last an initial three weeks starting Tuesday, is "highly likely" to be extended until May or June, according to the Sun newspaper, with police forces being told to prepare for a lockdown lasting up to six months, according to The Daily Telegraph.

Under the new rules, British people are barred from leaving their homes for anything other than the following "essential" activities:

Shopping for basic necessities as infrequently as possible.

One form of exercise a day — for example a run, walk, or cycle — alone or with members of your household.

Any medical need to provide care for or to help a vulnerable person.

Traveling to and from work, but only if absolutely necessary and if the work can't be done from home.

To ensure the lockdown is obeyed, Johnson also announced he would close all shops selling "nonessential goods" as well as playgrounds, libraries, and places of worship.

He also announced:

A ban on gatherings of more than two people in public, excluding those people who live together.

A ban on "weddings, baptisms, and other ceremonies but excluding funerals."

The new rules are to be enforced by the police with fines imposed on those who refuse to comply.

Fines will reportedly begin at £30 but could rise to £1,000 for repeated infringement under emergency legislation introduced this week by the UK government.

The prime minister said all in-person social interactions had to come to an end to beat the virus.

"You should not be meeting friends," he said. "If your friends ask you to meet, you should say, 'No.' You should not be meeting family members who do not live in your home."

Johnson's decision followed a weekend in which images of British people defying his government's advice to stay at home were shared widely on social media and in the British press.

Watch Boris Johnson announce a full UK coronavirus lockdown

—UK Prime Minister (@10DowningStreet) March 23, 2020

Johnson's political opponents cautiously welcomed the announcement Monday evening.

"The prime minister is right to call for people to stay at home, protect our NHS and save lives," the Labour Party's leader, Jeremy Corbyn, said. "This is the right response to the coronavirus pandemic, and one we have been calling for.

"There now needs to be clear guidance to employers and workers about which workplaces should close — and the government must close the loopholes to give security to all workers, including the self-employed, as well as renters and mortgage holders.

"We welcome these moves and will be working to ensure everybody has the protection and security they need."