Away from central London's hustle and bustle, a group of intrepid swimmers from the Serpentine Swimming Club (SSC) complete a morning ritual of plunging into the chilly waters of Hyde Park.
From 6:30 am each day come rain or shine - or even ice - members enjoy the refreshing temperatures of the Serpentine Lido while others start their commute to work, sharing the dark waters in one of the city's largest parks with a few inquisitive swans.
On Thursday, a black board by the side of the pool warned the waters were a cool 10 degrees Celsius with a dog watching from the pontoon as the swimmers jumped in.
"Swimming pools are hot, sweaty, there is a lot of noise. People who like swimming usually like swimming outside," the club's President Robin Hunter Coddington said. "We don't like wetsuits."
"If you like swimming, the fewer clothes the better."
The SSC is the oldest swimming club in Britain, the Royal Parks said, with the club organising races on Saturdays for potential new recruits.