Boris Johnson said that Covid-19 "is the worst public health crisis for a generation", the Prime Minister has said as the Government's top scientist warned that up to 10,000 people in the UK are already infected.
The PM introduced new measures to try and protect the elderly and vulnerable, saying anyone with coronavirus symptoms, however mild, such as a continuous cough or high temperature, must now stay at home for seven days.
Schools in Italy and Ireland are closed and America banned incoming flights. But according to the British experts drastic measures require the support of the public - and so when they are introduced is important.
Prof Whitty said: “The important part of the science of this is the behavioural science.
“People start off with the best of intentions [of following the rules] but if you start too early then people’s enthusiasm starts to run out just about the peak.
“Which is the time we want people to be doing these interventions, that is not a productive way to do it.
“So we do need to it at the last point it is reasonable so that people retain their enthusiasm through what will actually be things which are quite difficult to do.”
ITALY
More than 1,000 people have now died in Italy from Corona Virus, with the total number of cases rising to at least 15,000 on Thursday.
The country has closed almost all shops except food stores and pharmacies.
Bars, restaurants, Gyms, schools, museums and hairdressers have also been closed.
A national quarantine has been imposed, restricting the movement of people except for work, health and other essential reasons.
SPAIN
Some 2,182 cases have been reported in Spain, mainly in the Madrid region -with 49 deaths so far.
On Monday, PM Pedro Sanchez ordered schools and universities to close for two weeks to try and slow the spread of the virus.
Flights to and from Italy have been cancelled and working hours have been reduced.
FRANCE
France has reported almost 2,876 confirmed cases and 61 deaths from coronavirus.
Nurseries and schools will be closed for 15 days in some areas. Major sporting events have been cancelled and visits to retirement homes have been banned.
President Emmanuel Macron said forthcoming local elections would still go ahead and public transport would continue to operate.
But the elderly and people with health issues have been urged to stay at home for as long as possible.
The state will take on the salaries of those who have to work from home and taxes due in march will be postponed.
REPUBLIC OF IRELAND
Ireland recorded its first death linked to coronavirus, with a total of 43 confirmed cases.
PM Leo Varadkar announced schools, colleges and childcare facilities will be closed until March 29.
Outdoor gatherings of more than 500 people, and indoor gatherings of more than 1,000 people will be cancelled.
DENMARK
All schools and universities have been closed in Denmark, with public sector employees with non-critical jobs told to work from home for at least 14 days.
Some 514 people had been diagnosed with coronavirus in Denmark, but none have died so far.
NORWAY
Norway has implemented strict travel bans to and inside the country - forcing anyone entering from outside the Nordic countries to enter quarantine even if they have no symptoms. Schools and colleges have been closed and cultural and sports events cancelled.
Gyms, hairdressers and swimming pools have all been closed.
More than 700 cases have been confirmed, but none have died so far.
GERMANY
Five people have died out of a reported 1,296 cases in Germany - though independent tallies claim the true figure is much higher.
Large events with more than 1,000 attendees have been cancelled and workers have been encouraged to work from home.
The Bundesliga has announced several upcoming football matches will be played in empty stadiums.
USA
Donald Trump announced a sweeping ban on travel to the US from European countries - which does not, so far, include the UK.
New York Governor Andrew Cuomo has implemented a ban on events with more than 500 people - forcing the bright lights of Broadway to go dark and theatres to shut for a month.
The National Guard has been deployed in New York, schools have been closed in some areas and mass-gatherings have been banned in California.
At least 39 Americans have died so far - with more than 1,300 cases reported so far.
CHINA
Some 3,169 people have died in China, where the virus originated, with 80,932 cases reported.
The government has implemented strict social distancing and 14 day quarantines for overseas visitors.
IRAN
Public gatherings and prayers have been cancelled in Iran - and schools have been closed.
Authorities have temporarily released around 70,000 prisoners - not including political prisoners - to try and contain the spread of the disease.
Trains, buses and public areas have been disinfected.
A total of 9,000 cases and 429 deaths have been reported.
