Taking a dip in the frigid ponds on Hampstead Heath in north London for the first time after months of coronavirus restrictions, swimmers said plunging into the cold water felt liberating.
Not long after dawn, dozens of them broke the pond's surface to the sounds of birdsong, undeterred by eight degrees Celsius (46.4 degrees Fahrenheit) water temperature chalked up on a lifeguard's board.
"You do feel cold but you feel really good afterwards and it's sort of worth it," Margaret Dickenson told AFP.
The septuagenarian, who has been swimming regularly in the ponds for the last 30 years, added the activity was "a way of getting a lot of exercise painlessly".
Since Monday, restrictions on practising outdoor sports have been lifted in England after a national lockdown was imposed in early January.
The easing follows a months-long vaccination campaign which officials have credited with drastically reducing the number of coronavirus cases, hospitalisations and deaths.
In north London, the reopening of the ponds on Hampstead Heath have been eagerly anticipated by swimmers who dive among the ducks and mud almost every day.
The huge 320-hectare park in the British capital has three ponds for swimming: one reserved for women, another for men and a third for mixed bathing.
"There are few things better than the simple pleasure of immersing yourself in cold water," Joe Pundek, 29, said by the side of the mixed pool, surrounded by greenery and bathed in early-spring sunshine.
"In a world and in a life where we are surrounded by a lot of rules and technology and problems, the act of swimming in a pond, especially cold water, is very raw and very pure," he added, his teeth chattering slightly.
- Embracing rivers, lakes -
On a pontoon, swimmers slipped into the water and did a few strokes before emerging with their skin slightly reddened by the cold and wrapping themselves in towels.
Paid membership of the Mixed Pond Association jumped by nearly 50 percent last year, reflecting a recent surge in the appeal for open water swimming in lockdown as gyms and leisure centres were shuttered.
"With pools shut and people looking for outdoor exercise close to home, thousands of people have made this the time to embrace rivers, lakes and the sea," Kate Rew, the founder of the Outdoor Swimming Society (OSS) explained.
Since Britain's first nationwide lockdown in March last year, OSS memberships have risen by 36 percent to 136,000 and the website traffic has increased by 46 percent to 785,000 unique users.
Swimming in nature, Rew said, is "free, healthy and makes people feel part of the planet, and it's all about self-sufficiency and stoicism -- making it a perfect activity for these challenging times".
The dramatic rise in wild swimming over autumn led to a 52 percent increase in swimming-related incidents over the preceeding four months, the coastguard said in December.
The rescue service recommended swimmers make sure they check weather conditions before taking to the water and trying to swim with someone, emphasising the risk of hypothermia and memory loss from exposure to cold waters.
Sue Hodge, a 66-year-old swimmer, told the BBC her short-term memory had been "obliterated" after she took a dive into the waves off the coast in Cornwall, southwest England, in November and ended up in hospital.
In Hampstead Heath, it is the first time the ponds have opened so early in the year due to high demand despite the low temperatures.
Swimmers in the capital have also flocked to the Serpentine Pond in central London's Hyde Park, where a dip is also permitted.
But in an effort to temper the enthusiasm, lifeguards have urged swimmers to remain cautious and to enter the water gradually until warmer days return.