British Prime Minister Boris Johnson has ordered people to stay in their homes to try to halt the spread of coronavirus.
As deaths from the virus in Britain jumped by 54 to 335, the government said the military would help ship millions of items of personal protective equipment (PPE) including masks to healthcare workers who have complained of shortages.
"From this evening I must give the British people a very simple instruction - you must stay at home," Johnson said in a televised address to the nation, replacing his usual daily news conference.
Johnson said people would only be allowed to leave their homes for basic necessities: exercise, for a medical need, to provide care or travelling to and from work where absolutely necessary.
"If you don't follow the rules the police will have the powers to enforce them, including through fines and dispersing gatherings."
The government will close all shops selling non-essential goods, Johnson said, including clothing stores, as well as other premises including libraries, playgrounds and outdoor gyms, and places of worship.
The measures will be reviewed in three weeks.
Advice to stay at home and avoid social gatherings went unheeded by millions at the weekend who took advantage of sunny weather to flock to parks and beauty spots, ignoring instructions to stay 2m apart.