A 22-year-old man has been arrested after he climbed over a security fence at Buckingham Palace, police have said.
The man from Croydon, south London, was arrested in the early hours after he was seen by officers who were monitoring CCTV cameras.
He was arrested at 04:15 BST within a security perimeter. He did not gain access to the palace.
The Met said the suspected intruder had been drinking and that the incident was not thought to be terrorism related.
The force added the man was not armed and no Taser was deployed by officers.
He is currently being held in a central London police station.
No member of the royal family was in residence.
A Buckingham Palace spokesperson declined to comment.