Police say they are "fighting a losing battle" over enforcing the lockdown after "hundreds" turned out in parks across east London to enjoy picnics in the sunshine.
Officers in Hackney said groups were gathering in the borough's parks to have "pizzas, beers, wines", despite social distancing rules and calls from the Government for people to stay at home this weekend.
It comes after the Coastguard said that Friday had been its busiest day since lockdown began, with 97 call-outs, compared to the average for April of 63.
Boris Johnson is due to outline potential changes to the lockdown rules on Sunday, but has insisted any alterations will be "limited".
It is thought that people might be permitted to spend more time exercising outside as part of the changes.
Currently, however, people are only supposed to leave home for work, food, exercise or health reasons and must maintain the two-metre social distancing rule when they are outside of the house.
A Hackney Police statement, posted today on its official Twitter page alongside an image thought to be of London Fields, said: "Sadly we're fighting a losing battle in the parks today.
"Literally hundreds of people sitting having pizza, beers, wines. As always a big thank you to those that are observing the guidelines."
Victoria Park, in east London, was closed earlier during the lockdown after the council said there were too many people breaching social distancing guidelines.
Similarly, Lambeth Council closed Brockwell Park after more than 300 sunworshippers breached lockdown rules.
Previously, Health Secretary Matt Hancock suggested if people continued to break rules – one form of fitness a day while staying at least two metres from others – then all outdoor exercise could be banned and park gates closed.
However, Secretary of State for Housing, Communities and Local Government Robert Jenrick said he disagreed with decisions to close green spaces, and had "made it clear" to councils that parks need to remain open to help those with limited living space.
The police's tweet came as some VE Day street parties were criticised for allegedly breaching lockdown rules.
Residents of a street in Cosham, a suburb of Portsmouth, were among those who celebrated VE Day with a street party, while residents near Warrington came under fire for performing a "socially-distanced" conga.
