A 59-year-old man arrested outside Buckingham Palace days before the Coronation will receive care in hospital.
A man who was arrested outside Buckingham Palace on Tuesday has been detained under the Mental Health Act.
Police were called to reports a man had thrown shotgun cartridges into the grounds, and carried out a controlled explosion on a bag.
A 59-year-old was arrested at the scene and was found to be in possession of a knife.
He will receive medical care in hospital while on bail.
No-one was injured in the incident and the Metropolitan Police said it was not being treated as terror-related.
The King and the Queen Consort were not at Buckingham Palace at the time of the arrest, but the King had hosted Australian Prime Minister Anthony Albanese there earlier on Tuesday.
The Palace has not commented in the incident.