Security concerns raised after incident at Buckingham Palace.

A man carrying a suspicious package and a knife who had camped for days allegedly ranting he was going to kill the King threw suspected shotgun cartridges into the grounds of Buckingham Palace before he was arrested last night. The palace was on lockdown yesterday after the Metropolitan Police detained the man at about 7pm after he approached the gates in central London and threw a number of items. The man is being held on suspicion of possession of an offensive weapon after a knife was found, the force said. The incident is being treated as an isolated mental health incident and not terror-related.