Both anti-monarchy demonstrators and Just Stop Oil environmentalists have accused the Met police of denying peaceful protest, as ITV News Global Security Editor Rohit Kachroo reports
Arrests were made for offences "including affray, public order offences, breach of the peace and conspiracy to cause a public nuisance," they said, adding that all of the 52 remain in custody.
The police operation surrounding Saturday's events was one of the UK's biggest ever - with more than 11,500 officers involved.
Commander Karen Findlay, who led the policing operation as Gold Command, said the context of the King's coronation as a "once in a generation event" meant that they had a duty to intervene.
Those arrested even before the service had started included Republican, Just Stop Oil and Animal Rising protesters.
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Demonstrators were detained just hours before the ceremony, as protests took place in London and Cardiff.
Royal fans cheered and shouted "see you later" as Just Stop Oil protesters were removed from The Mall.
Officers were seen carrying protesters from the area while crowds heckled and booed them.
People could be heard saying "what a waste of time" as the demonstrators were taken away.
The Met Police gave a breakdown of the arrests, including 14 made on The Mall - a road that runs from Buckingham Palace.
Just Stop Oil said approximately 13 demonstrators had been arrested on The Mall ahead of the coronation, and five more were arrested at Downing Street.
A spokeswoman said the group’s plan was "only to display T-shirts and flags", adding: "This is a dystopian nightmare".
The Met also confirmed, late on Saturday evening, that it had arrested three people in the early hours of the morning of the coronation on suspicion of conspiracy to commit public nuisance.
Officers said they seized a number of rape alarms on Saturday, after receiving intelligence that the devices would be used to scare military horses used within the procession.
All three individuals have since been released on bail pending further enquiries.
Earlier, footage on social media appeared to show Graham Smith, chief executive of the anti-monarchy group Republic, being apprehended by police in St Martin's Lane, Westminster.
The anti-monarchy campaign group confirmed Mr Smith and five other members of its group had been arrested.
Harry Stratton, 30, who is the group's director, said he witnessed Mr Smith and other Republic members get arrested at around 7am as they brought placards to the demonstration.
Mr Stratton said: "They were carrying placards that were saying 'not my King' when around 20 police said 'we are stopping you and we are searching you'.
"Graham and our volunteers asked why and they said 'we will find that out'.
"After that they arrested them saying 'we are seizing all these placards' and Graham said 'why are you arresting us?'"
Animal Rising said a number of its supporters were apprehended on Saturday while at a training session “miles away from the coronation”. Nathan McGovern, spokesman for the campaign group, described the arrests as “nothing short of a totalitarian crackdown on free speech and all forms of dissent”. In Wales, hundreds of people joined a march through Cardiff city centre in protest of the monarchy as the King was crowned.
Nick Wall, member of campaign group Republic and chairman of the Labour For Republic organisation said: "A number of our activist leaders have been arrested today [in London] and it's actually an absolute disgrace.
"I felt compelled to say a few words because one of Republic's co-ordinators, his name is Ben and he's only 21 years of age, and he's been arrested. It's appalling."
In the nationalist area of Falls Road, in Belfast, around 50 people held a protest against the coronation.
They stood in the middle of the road holding placards which read 'Not Our King'.
As gun salutes were held for the King at Edinburgh and Stirling castles, protests were held across Scotland.
In Glasgow, All Under One Banner - which campaigns for Scottish independence - held a march from Kelvingrove Park to Glasgow Green. Organisers said 20,000 people attended.
Former first minister Alex Salmond, leader of the nationalist party Alba, rallied the crowd in Scotland's second-biggest city.
Mr Salmond told the crowd: "In London, the subjects are required to swear an oath of allegiance to the Crown.
"In Scotland, in Glasgow, the citizens choose to swear an oath of loyalty to Scotland."
Our Republic, which wants an elected head of state, also staged a protest in Edinburgh.
The event, on Calton Hill, saw Scottish government minister and Scottish Greens co-leader Lorna Slater speak, as did SNP MP Tommy Sheppard and Green MSP Maggie Chapman.
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Non-profit campaign group Human Rights Watch said the arrests ahead of the coronation were "something you would expect to see in Moscow not London".
Meanwhile, Amnesty International UK's chief executive Sacha Deshmukh said the human rights group had been concerned about Metropolitan Police statements about its "low tolerance" of protests ahead of the coronation arrests.
On Wednesday, the Metropolitan Police announced they would have an "extremely low threshold" for protests during the coronation celebrations, and that demonstrators could expect "swift action".
Republic demonstrators could be seen wearing yellow "Not My King" T-shirts and carrying placards as they protested at Trafalgar Square ahead of the coronation.
In pictures shared across social media, police could be seen loading confiscated yellow placards into the back of a police van.
In one video, an officer says: "I'm not going to get into a conversation about that - they are under arrest, end of."
Met Police commander Karen Findlay, who led the policing operation, said: "We absolutely understand public concern following the arrests we made this morning. Protest is lawful and it can be disruptive. "We also have a duty to intervene when protest becomes criminal and may cause serious disruption."
Commander Findlay added: “This depends on the context. The coronation is a once-in-a-generation event and that is a key consideration in our assessment. A protest involving large numbers has gone ahead today with police knowledge and no intervention.”
Boos and opposing chants
At around 8.30am there were chants of "not my king" from a group of anti-monarchists standing at the edge of Trafalgar Square.
They were met by boos and opposing chants of "God save the King".
Supporters of campaign group Republic stood in the middle of the crowd waiting for Charles and Camilla's procession.
Chants of "you’re not singing over there" began on the right-hand side of The Mall, while a Mexican wave also started halfway down the road.
Charles-themed £1 million notes were being handed out to the crowd.
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Many of the campaigners were dressed in yellow waving placards with slogans including "king parasite" and "abolish the monarchy".
They were shoulder to shoulder with royal supporters bedecked in Union flags, with one waving a banner carrying a photo of Diana, Princess of Wales.
Home Secretary Suella Braverman thanked the police for their "hard work" amid the criticism of the arrests.
She said: "I'd like to thank the police for all their hard work at today's celebration to ensure it was safe and passed without incident.
"It was a magnificent procession and ceremony enjoyed by tens of thousands of people in London. It was a great tribute to our country and monarchy."