Police said the man had approached Buckingham Palace gates and thrown items, suspected to be shotgun cartridges, into the palace grounds before being detained by officers at around 9.00pm.

“The man has been arrested on suspicion of possession of an offensive weapon after he was searched and a knife was found,” London’s Metropolitan Police said in an updated statement.

The statement said police were not currently treating the matter as related to terrorism.

Police and security services are preparing for King Charles’ coronation on Saturday, which is expected to see large crowds line the streets of London and heads of state from around the world attend the formal ceremony.

Buckingham Palace said neither the king nor his wife Camilla were at the palace at the time of Tuesday’s incident.

The statement said specialists had conducted a controlled explosion as a precaution. Cordons had been put in place after the man was found to have a suspicious bag, but these cordons had now been removed.

“There have been no reports of any shots fired, or any injuries to officers or members of the public,” said Chief Superintendent Joseph McDonald.

In 2016, an unarmed man was arrested in the grounds of Buckingham Palace after scaling a perimeter wall. In 2021, a man was arrested at Windsor Castle on Christmas Day wearing a mask and holding a crossbow.