More than 29,000 police officers will take part in one of the UK's "most significant" ever security operations for the coronation of King Charles III this weekend, police said Wednesday.
Some 2,000 guests, including global royalty and world leaders, will be at Saturday's event in central London, with huge crowds lining the route to and from Buckingham Palace.
The government earlier insisted that security services were "ready to deal" with the challenges a man was arrested on suspicion of throwing shotgun cartridges into the grounds of Buckingham Palace.
Police detained the man, who was allegedly armed with a knife, at about 7:00 pm (1800 GMT) on Tuesday, causing concern just days before the historic event, which is the first coronation in Britain since 1953.
Security minister Tom Tugendhat told Times Radio that police were "all over" the challenges presented by the coronation.
"Our intelligence and other security forces are extremely aware of the challenges that we face and ready to deal with them as the police did quite brilliantly yesterday," he said.
The drama unfolded after the man approached the gates to the palace and threw several items into the grounds suspected to be shotgun cartridges, according to the Metropolitan Police.
They have been recovered and will be taken for specialist examination.
Police said the man was arrested on suspicion of possession of an offensive weapon after he was searched and a knife was found, but that it was not treating the matter as terrorism-related.
Neither Charles, 74, nor his wife Queen Consort Camilla, 75, were at the palace at the time, British media said.
Golden Orb
The Mall, leading to Buckingham Palace, has been closed off to traffic in preparation for Saturday's coronation, which is the first to take place in Britain for 70 years.
Thousands of ceremonial troops will take part in a procession from Buckingham Palace to Westminster Abbey as part of the coronation.
Dress rehearsals took place overnight Tuesday to Wednesday.
The security operation to protect the route to and from the abbey -- dubbed Operation Golden Orb -- will include rooftop snipers and undercover officers, as well as airport-style scanners, sniffer dogs and a no-fly zone over central London.
There will be more than 29,000 police officer deployments over the coming week and the coronation weekend, said the Met.
"Our tolerance for any disruption, whether through protest or otherwise, will be low," police said Wednesday, adding it was "one of the most significant and largest security operations" in its history.
"We have been planning for this occasion for some time; the Met has a long history of policing such events and we will draw upon our diverse expertise," said Met Deputy Assistant Commissioner Ade Adelekan.
"On Coronation Day we will have the largest one-day mobilisation of officers seen in decades with just over 11,500 officers on duty," he added.
Buckingham Palace has rejected reports that the security operation would cost at least £100 million ($125 million), raising eyebrows -- and complaints -- as many Britons struggle with the soaring cost of living.
"I've seen a number of different estimated figures floating around, some more fanciful than others," a palace spokesperson told reporters.
"A national occasion like this, a great state occasion, does attract huge global interest that more than repays the expenditure that goes with it."
New police powers to stop protests have been brought forward to ensure that roads and footpaths remain open during the celebrations, said Tugendhat.
The streets of the British capital have in recent years been blocked by environmental protesters, and republicans opposed to the monarchy say they will stage a demonstration on the procession route.
"The police need to have extra powers to move people on. I think that's perfectly reasonable," said Tugendhat.