London's outdoor swimming pools, known as lidos, have implemented stricter security measures in response to a surge in antisocial behavior this summer. Incidents including assaults on lifeguards, large-scale brawls, thefts, and unauthorized gatherings have forced some facilities to close temporarily and implement new entry and safety protocols.
Parliament Hill Fields Lido in Hampstead Heath experienced closures twice this summer due to "inappropriate behavior." Witness accounts describe youths forcing their way onto the premises, consuming alcohol, and engaging in fights. One incident on the May Bank Holiday weekend saw a swimmer struck over the head with a stolen wine bottle, resulting in hospitalization. Lifeguards attempting to intervene were reportedly pushed into the water. Following this event, the City of London Corporation, which manages the lido, introduced a ban on under-16s entering without a parent, random bag searches, additional security personnel, and mandatory ID checks. High walls have also been erected to deter unauthorized entry.
Despite these measures, further disturbances have occurred. Shortly after the new rules were imposed, another fight reportedly broke out among individuals queuing for entry. In May, swimmers also caused disruptions at the nearby Model Boating Pond, a protected wildlife area, ignoring "no swimming" signs and disturbing nesting birds and ducks. Similar scenes were observed at Ruislip Lido in west London, where large crowds entered the water despite red flags indicating unsafe conditions and a lack of lifeguard supervision.
This increase in problematic behavior coincides with a prolonged period of hot weather and a rise in visitor numbers to London's outdoor pools. Between June and August 2025, three pools run by the leisure company Better—London Fields, Charlton, and Oasis—saw a 30% increase in visitors compared to the previous year, reaching over 524,000. Experts suggest that the combination of intense heatwaves and large crowds can heighten tensions among visitors, particularly casual attendees who may have unrealistic expectations of a poolside experience.
Other lidos have also adapted their security. Tooting Bec Lido, the largest outdoor pool in the country, has increased its security presence, with guards checking bags and issuing wristbands for entry. While the facility can accommodate over 3,300 visitors daily, security guards report that overcrowding is a more common issue than aggravated customers. They acknowledge that large gatherings in public spaces, such as festivals or busy pools, can present similar challenges.
The Metropolitan Police confirmed that officers responded to an altercation at Parliament Hill Fields Lido on May 25, where a 15-year-old boy and a man in his 40s sustained minor injuries. A 17-year-old boy and a 25-year-old man were arrested on suspicion of affray. Investigations into the incident are ongoing.