A 16-year-old boy has gone missing in a south-east London lake after getting into difficulty in the water.
Emergency services were called at just after 15:00 BST to Beckenham Place park.
The park has been evacuated so that they can carry out a co-ordinated search, the Met said.
The boy’s family have been told and are currently being supported, the force added.
The lake is 285m (about 935ft) long and reaches depths of up to 3.5m (about 11ft).
The London Ambulance sent their hazardous area response team, alongside ambulance crew.
London Fire Brigade also has 35 firefighters and five fire engines at the scene. Crews have been sent from Woodside, Lewisham, Beckenham, Croydon and Euston.
Lewisham Council has said it is supporting police on site.
On Monday, 11-year-old Kaliyah Coa went missing in the River Thames. A “recovery mission” is under way to find her, the Met said.
