Police have been given greater powers to tackle disruption to the King’s coronation under new laws that come into force today, but the arrest of a man outside Buckingham Palace overnight has highlighted security concerns.
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.
The arrest has highlighted concerns, as has an escalating series of road-blocking protests by the Just Stop Oil campaign group.
But police are alert to the potential for a much bigger threat from terrorists who could use the global live television coverage to publicise their aims.
Legislation that comes into force on Wednesday carries up to a year in jail for demonstrators blocking roads, airports and railways.
Anyone locking or gluing themselves to buildings or objects risks six months behind bars.
Police can also stop and search anyone they suspect is planning to cause disruption – one of the powers given royal assent by the King on Tuesday.
Read more on coronation:
How did Camilla successfully rebrand her image after ‘tampongate’
Write your coronation message for the King here
Details of the new laws were outlined in a Home Office letter sent to various protest groups, some of whom reportedly condemned the move as “intimidatory”.
Police will have assembled an intelligence database of likely demonstrators and in the past, ahead of major public events, have visited known individuals to try to ask them about their intentions.
Anti-monarchist Patrick Thelwell, 23, who was fined last year for throwing an egg at the King in York, is urging others to join him at a Coronation Day “Not My King” protest in central London, but has asked demonstrators not to bring eggs.
It comes as Security Minister Tom Tugendhat said the government is “in no way complacent” about security surrounding the King’s coronation after the arrest outside Buckingham Palace.
He said he was “very proud” of the way the police responded to the incident.
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.”
Buckingham Palace confirmed neither the King nor Queen Consort were at the palace at the time of the incident.
Scotland Yard said they are not treating the incident as terror-related.
Asked how much security for the coronation would cost the taxpayer, Mr Tugendhat was unable to give a figure.
He said: “It’s very difficult to pull that out as a separate figure for the simple reason that we’ve got an enormous amount of effort going in for a major incident like this in different parts of the country – because there are people getting together in streets, there’s people getting together in gatherings across the country because this is a moment of national celebration.
“What I think is worth looking at, though, is how much this is bringing to the country in terms of the number of tourists who are coming, the amount of attention that is coming and indeed, I hope, the amount of business that will be generated by heads of state and government and other business people coming to the UK at this time to see what we offer.”
Pressed on figures of at least £100m just for security, Mr Tugendhat said: “It’s not a figure that I recognise, sorry.”
He said: “Forgive me for not being able to break it down at this point.
“The reason I don’t want to do that is because there’s police forces around the country who are doing different things and answer slightly differently through their own different structures.”
He said he did not have a number for how much it was costing the Metropolitan Police, but added: “What I’ve been doing is making sure that the Met are ready, and that means preparing with them and the National Crime Agency and the intelligence services to make sure they have all the resources they need.
“We have spent an awful lot of time over the last several months preparing for any number of different threats because the reality is this is a very complex event.”