By Noah Vickers, Local Democracy Reporter
Sir Sadiq Khan has been warned that his promise to create “swimmable rivers” in London by 2034 must not encourage people to swim in the dangerous tides of the Thames.
The mayor was re-elected last year on a manifesto which pledged he would “make rivers in London swimmable within ten years, working with partners to reverse the damage done to our rivers and waterways”.
But at a Thursday meeting of City Hall’s environment committee, a senior official at the Port of London Authority (PLA) – which manages the tidal section of the Thames – said the way in which the plan had been summarised in media headlines had caused some concern among her colleagues.
Grace Rawnsley, PLA’s director of sustainability, said: “We’ve worked really hard over the last 15 years to reduce the number of deaths that we get in the Thames.
“In 2023, I think there were 31 deaths in the tidal Thames, from people going in when they shouldn’t have gone in, or accidents.
“In 2022, I believe 109 rescues happened in the tidal Thames, from people going in.
“So it’s about that knowledge, it’s about doing it in a safe way, and certainly in the tidal Thames we would always be discouraging that swimming.
“But I think when we get headlines like ‘swimmable Thames’, it does mean that people think that it’s safe to swim in. So it’s really important to have that kind of messaging about how you do that safely.”
The Thames is tidal for almost its entire course through London, only becoming non-tidal at Teddington Lock.
Between Teddington Lock and Putney Bridge, the PLA allows, but does not “encourage”, swimming, Ms Rawnsley said.
Figures released by the Environment Agency show Thames Water spilled sewage into the River Graveney – a tributary of the River Wandle – 127 times in 2023 (Picture: Liberal Democrats)
Any swimming in the Thames east of Putney Bridge is completely prohibited, as the PLA points out that, among other dangers, “powerful tides running at around five miles an hour will overpower even the strongest swimmers”.
The Authority said that the tidal Thames is also the UK’s busiest inland waterway, accommodating more than 20,000 ship movements and hosting more than 400 events each year.
A spokeswoman for Sir Sadiq said: “The Thames and its tributaries are the lifeblood of London, which the mayor is committed to cleaning up and protecting.
“The tidal part of the Thames will never be safe to swim in, but the Port of London Authority is responsible for ensuring this water is more generally safe and accessible to the public.
“The mayor was delighted that the Port of London Authority joined him in pledging to turn the tide on our neglected waterways.”
In September, Sir Sadiq’s office published a map highlighting where Londoners can safely engage in ‘wild swimming’.
A passage of text on the map stated that “the tidal Thames is not safe to swim in”, and it instead suggests Londoners enjoy locations like Hampstead Ponds, the Serpentine in Hyde Park, and the Royal Docks next to City Hall.
The map said that swimming in the Thames at Teddington, and at Albany Reach near Hampton Court Palace, is “currently too polluted and unsupervised to be safe”.
But, it adds: “The mayor is committed to exploring whether these locations could be made swimmable in the future”.
The main focus of the mayor’s plans involves improving the quality of the water in London’s rivers and enabling them to support more wildlife.
His team says he will achieve this by “continuing to push Thames Water to address damaging sewage spills, expanding the installation of sustainable drainage systems, tackling sewer misconnections, and funding reedbeds and other solutions that naturally filter the water in London’s rivers”.
Pictured top: London mayor Sadiq Khan (Picture: Noah Vickers)