Officers were called to the park shortly after 3pm on Friday (April 4) following reports that a boy had gone missing after getting into difficulty in the water.
Specialist diving teams responded, along with the London Ambulance Service and London Fire Brigade.
A boy was recovered from the lake at around 10.42pm that evening.
He was taken to hospital, where he was sadly pronounced dead.
Police say the death is being treated as “unexpected” but not believed to be suspicious.
His family have been informed and are being supported by specially trained officers.
A Met spokesperson said: “Met Police has suspended a search for a 15-year-old boy at Beckenham Place Park, following the discovery of a body.
“Officers were called to the park shortly after 15:00hrs on Friday, 4 April following reports of a boy going missing after getting into difficulty in the water.
“Specialist diving teams were in attendance alongside the London Ambulance Service and London Fire Brigade.
“A boy was recovered from the lake at around 22:42hrs on Friday, 4 April.
“He was taken to hospital where he was sadly pronounced dead.
“His death is being treated as unexpected but not believed to be suspicious.
“His family are aware and continue to receive support.”
