London lidos chaos as brawls force increase in security during heatwaves

London’s lidos are experiencing a summer of anti-social behaviour, with many imposing stricter security measures following a series of chaotic incidents.

A number of break-ins and fights, often fuelled by alcohol, has caused Parliament Hill Fields Lido in Hampstead Heath to close twice in the past weeks - with one incident reportedly seeing a man having a bottle smashed over his head.

Temperature soared above 38C on Thursday during the fifth heatwave of the year, with unprecedented numbers swarming to London's outdoor swimming spots as a result.

But workers at lidos across the city say they have spent much of the summer contending with a “concerning” rise in anti-social behaviour.

The shocking incident at the Parliament Hill lido occurred over the May Bank Holiday weekend, when a group of youths were embroiled in a huge poolside fight while as lifeguards desperately attempted to restore order.

The lido was forced to close when someone was hit with a glass bottle during a brawl - while several members of staff were injured, two people were arrested and a vehicle was also damaged.

According to witnesses, the youths had forced their way on to the site.

A waitress at the lido's cafe told the Daily Mail: “We have a lot of break-ins. They stole a wine bottle from us and smashed it on this guy's head.

“A lot of them were really drunk and they pushed a lifeguard in. The man was bleeding across his head.”

The victim was taken to hospital - but the two people who were arrested were later released due to a lack of evidence.

Parliament Hill Fields Lido

AFP/Getty

Regulars say that such incidents are not uncommon, with a manager telling the Mail that brawls break out “every summer”, and that knives have been found concealed in visitors' bags.

He added: “We've had issues in the cafe too. We've had people trying to jump over the counter because they couldn't get booked in.”

The City of London Corporation, which runs the site, have since imposed stricter rules, including a ban on under-16s entering without a parent, random bag checks, and additional security.

Newly erected 10ft walls have been installed to deter intruders from scaling the perimeter.

However, within days, another fight broke out in the lengthy queue, resulting in the lido shitting for two consecutive evenings due to “poor behaviour”.

Furious residents accused swimmers of showing a lack of respect, with one local saying: “They are violating absolutely everything it's supposed to be and it's so upsetting.”

A woman wades through the water nears some swans in Hampstead Heath's wildlife ponds

Swans of Hampstead Heath / Instagram

The site was flying a red warning flag, which typically means there is no lifeguard on duty and there are hidden hazards present, such as poor water quality or toxic algae.

Organisers at Tooting Bec's pool have also increased security over the summer in a bid to tackle the surging attendances.

The country’s largest outdoor pool, the site welcomes more than 3,300 visitors each day during the summer, with wristbands mandatory and up to six security guards patrol on peak days.

Leisure company Better, which operates the London Fields, Charlton and Oasis sites, have said that 524,988 people visited their pools between June and August 2025, a 30% jump on the previous year, and a figure that is expected to grow again this summer.

Brockwell Lido in south London

PA

Jem Collins, founder of the online guide All The Lidos, says the anti-social behaviour is caused by casual visitors, rather than those who attend year-round.

She said: “I do think that this summer there have been more incidents than I've been aware of recently, and that is due to the heatwave. It got hot in May and it really hasn't stopped.

“You have 500 to 1,000 people queuing outside of a pool, getting hot, and waiting to get in. That's when tensions start to rise and things start to fizz.

“I think sometimes people have an expectation that they're going to be sat by the pool with a cocktail, almost as if they're abroad, but that's not really what lidos are like in the UK – you wouldn't find a poolside bar anywhere.”

Regarding the Parliament Hill Fields Lido incident in May, a Met spokesperson said: "At around 16.56hrs on Monday, 25 May, officers were called to reports of an altercation at Parliament Hill Fields Lido, Camden.

“Officers attended the scene and located a 15-year-old boy and a man in his 40s with minor injuries. A boy, aged 17 and a man, aged 25 were arrested on suspicion of affray.

“Anyone with information is asked to contact police on 101, quoting CAD5578/25MAY, or Crimestoppers anonymously on 0800 555 111."