Grounds, gardens and forests across the North East will close after thousands of people were seen outside in close proximity to each other over the weekend.
On Sunday, Boris Johnson said he would not be closing parks or enforcing a 'lockdown' in a bid to prevent the spread of Covid-19.
But he urged people not to "think that fresh air in itself automatically provides some immunity" after people across the country were said to be ignoring social distancing rules, gathering in large crowds in parks, beaches and hiking spots.
Bosses at the Alnwick Garden announced on Sunday that the popular Northumberland attraction would be closed to the public as the numbers of visitors might not stay low enough to ensure social distancing.
Meanwhile, the National Trust, which had previously offered access to its parks and grounds for free to enable people to get outside while practising social distancing, has now said its properties will be closed to stop the spread of coronavirus.
The charity's houses and other properties, along with cafes and shops, have already closed.
Director general Hilary McGrady said that after examining the numbers visiting over the weekend: "I am no longer convinced we can maintain social distancing over Mother’s Day when numbers are likely to grow, and beyond."
Mark Brassell, Alnwick Garden director, said: “It has been a tough decision to close The Garden but the safety of our visitors, staff and volunteers are paramount.
"We have been closely following the government guidance regarding social distancing and until now our visitor numbers have been low enough to comply with that guidance. This is something we can’t now guarantee...
"I know it’s a disappointment for many, but we will be back as soon as the crisis has been averted.”
All recreation facilities in woods and parks managed by Forestry England, which operates car parks, toilets and other facilities in many rural areas including in the Northumberland National Park, will also be closed from Sunday night.
