The Prime Minister has ordered people to stay at home with immediate effect
The police will fine and disperse those who break the rules.
People can now only leave their home to:
Shop for essentials
Take one form of exercise a day
For a medical need
To care for a vulnerable person
To travel to and from work, but only if absolutely essential
A ban of gatherings of more than two people excluding those you live with has also been announced.
Libraries, playgrounds and outdoor gyms, plus places of worship, to close.
Parks to remain open for exercise, but gatherings of more than two will be dispersed.
All social events, including weddings, baptisms and other ceremonies also stopped, but funerals can still take place.
Boris Johnson said the restrictions would be kept under constant review and would be looked at again in three weeks.
He said Coronavirus is "the biggest threat this country has faced for decades".