Wild swimming is all the rage. Forget chlorinated caged waters, head out to open waters flowing freely under the sky.
But there are downsides. In a recent swim at Hampton Court out of 700 swimmers 338 of them got "symptoms including diarrhoea, stomach cramps and vomiting."
Despite improvements Thames water is not known for their purity: over spills of sewage, then there's rats, ducks and cattle all doing their things plus rubbish, which included on yesterday's kayak a used condom.
But that didn't stop this band of enthusiasts brave the risks and cold along the banks of Chiswick.
Rather them than me to be honest.