A man has died after being found on fire outside Kensington Palace.
Officers were called to the London home of the Duke and Duchess of Cambridge at 03:42 GMT but the man was pronounced dead at the scene.
A Met Police spokesman said: "This incident is not being treated as terrorist-related."
The force said it was contacted by a London hospital shortly after midnight after a patient failed to return.
Officers were called to the palace three hours later, after reports of a man behaving suspiciously.
The man, aged in his 40s, was on fire when they arrived.
A spokesman for the royal family said the Duke and Duchess of Cambridge were not at the palace at the time.