The government is “in no way complacent” about security surrounding the King’s coronation after a man was arrested outside Buckingham Palace overnight, the security minister has said.

Tom Tugendhat added that he is “very proud of the response” to the incident.

A man was arrested after throwing what is suspected to be shotgun cartridges into palace grounds, the Metropolitan Police said.

A precautionary controlled explosion was carried out outside the palace and the man was held on suspicion of the possession of an offensive weapon, the force added.

Officers said a knife was found on him but he did not possess a gun.

Mr Tugendhat told Kay Burley on Sky News: “I’m very glad to see that the police reacted incredibly quickly, incredibly professionally, to the incident last night.

“We’re in no way complacent. And I’m very, very proud of the response that the police have done.

“The intelligence services, the police and others have been working on this extremely effectively for months.”

Asked how much security for the coronation would cost the taxpayer, Mr Tugendhat was unable to give a figure.

“It’s difficult to pull that out as a separate figure for the simple reason that we’ve got an enormous amount of effort going in in different parts of the country,” he said.