UK Prime Minister Boris Johnson is under mounting pressure to order a widespread lockdown after thousands of people ignored calls for "social distancing" to slow the coronavirus pandemic.
Mr Johnson said he will be thinking "very, very actively" about what steps to take if people continue to gather in large numbers in defiance of calls to stay apart.
Meanwhile letters are going out to 1.5 million people with underlying health conditions who are considered to be the most vulnerable to the coronavirus telling them to stay at home for the next 12 weeks.
The UK death toll from the pandemic rose by 48 in a day to 281 yesterday. There was anger among MPs at scenes over the weekend of crowds flocking to parks, markets, beaches and beauty spots.