Fragments of human and animal bones believed to be dating back to the time of the Blitz have been uncovered by children playing in Regent's Park.
The remains, along with burnt bricks, roof tiles and other debris were found in the central London park on 13 May.
Natural History Museum, which analysed the fragments, said the remains dated back to before 1941 and could have been deposited in the park after the Blitz.
Police said the findings were similar to bomb debris from World War II.
A spokesperson for the Royal Parks said: "On 13 May 2009 some school children found bone fragments on the soil surface while playing in Regent's Park.
"The police were immediately contacted and the area was secured."
Metropolitan Police said examination concluded it was an "archaeological find".
A statement from the Natural History Museum said: "They may be the remains of Blitz casualties.
"They may also be remains from a cemetery in the vicinity of the houses which were disturbed when the area was bombed, and then moved with the rubble."
The remains are being kept at the museum, the spokesperson from the Royal Parks said.
Germany carried out air raids across mainland Britain and bombed London for 24 nights in September 1940 during World War II.
The German air force dropped 5,300 tons of high explosives across the city, reducing several areas to rubble.