A visitor to the Parliament Hill lido on Hampstead Heath was taken to hospital after being hit with a glass bottle after a fight broke out.
Multiple members of staff were also injured during the altercation on May 25 during last month’s heatwave.
The fight broke out among two groups of young people, according to a City of London Corporation report, with a staff member’s vehicle also significantly damaged.
Two people were arrested in connection with the incident though have since been released.
The Corporation report, compiled by officers ahead of a Hampstead Heath Consultative Committee meeting next week, is the first time an authority has publicly acknowledged someone was hit with a glass bottle.
The Local Democracy Reporting Service (LDRS) revealed how a regular café user said they had heard one person had hit another over the head with a vodka bottle, though this was not confirmed.
The warm weather over the long weekend had led to long queues at the lido as people sought to escape the heat.
Reports on social media suggested waits of an hour and 40 minutes to get into the site.
Corporation officers wrote an initial verbal altercation developed into a fight between two groups, which continued outside the lido.
The Hampstead Heath Constabulary and the Metropolitan Police attended and one person was taken to hospital after being hit with the bottle.
A Met Police spokesperson said two individuals were arrested, both on suspicion of affray. They have since been released due to a lack of witnesses willing to confirm their involvement.
The LDRS understands the individual hit with the bottle was taken to hospital by someone else at the lido rather than the London Ambulance Service.
The Corporation’s report states: “Officers are investigating how glass was brought into the lido, where it is strictly prohibited, and are reviewing existing security footage and procedures for all swimmers. A complete review of operations at the lido has been initiated, including but not limited to capacity, staffing, safety, and admittance procedures.”
A second fight broke out on May 28 in the queue outside the lido, with further incidents caused by swimmers on the premises.
Since then the City of London Corporation, which manages the Heath as a registered charity, has introduced a series of measures to be in-place until September 5.
They include ID checks, no entry for anyone under 16 without a parent, guardian or responsible adult, and random bag searches.
Chair of the City of London Corporation’s Hampstead Heath, Highgate Wood and Queen’s Park Committee, Alderman Gregory Jones KC, said: “The behaviour of some visitors over the recent Bank Holiday was utterly appalling and will not be tolerated.
“No one should be subjected to abuse or violence. Keeping the public and our staff safe is our number one priority.
“Our Constabulary patrols the Heath and its facilities at no cost to the local council taxpayer. They will always seek to engage first, but we will take firm enforcement action when necessary.
“We are working closely with partners, including the Metropolitan Police Service, and considering extra measures to ensure that Hampstead Heath remains a safe and welcoming space for all.”
Shocking videos were also shared online of crowds of visitors to the Heath entering two non-swimming ponds.
Their activity disturbed and harmed wildlife, such as by overturning swan nests, and were widely condemned.
The Corporation has warned those who flout the rules moving forward risk being fined or arrested.
