British police say they have arrested 52 people during their operation to secure the coronation of King Charles III, and are holding them for a range of offences, including quarrelling, disturbing the peace and conspiring to harm the public.
London police said in a statement that all those arrested remained in detention.
Police defended the arrests, which were heavily criticized, saying they had "received information indicating that protesters wanted to disrupt the coronation procession".
"This included information indicating that individuals wanted to seek to vandalize landmarks with paint, breach barriers and obstruct official movements."
Police arrested dozens of environmental activists who were planning to disrupt the royal parade, as well as at least six anti-monarchists, including Republic leader Graham Smith, who staged a demonstration in Trafalgar Square.
But that didn't stop hundreds of supporters of republican rule from demonstrating as the royal procession passed, gathering amid crowds lining both sides of the King's Motorcade Road in central London wearing yellow shirts to distinguish them from the crowds dressed in red, white and blue, and holding signs reading "I am not mine."
Images circulating on social media showed security personnel confiscating protesters' banners.
Police did not confirm Smith's arrest, but said the troops acted because they believed protesters would seek to deface public shrines with graffiti and disrupt "official movements".
Rights groups have criticised the conduct of police, who deployed more than 11,<> officers on Saturday, and the arrests come days after a controversial new law was passed to strengthen police powers to tackle protests.
Protests also erupted in Glasgow, Scotland, and Cardiff, Wales, with banners reading "Abolished the property, feed the people". Many on social media spoke about Britain's cost-of-living crisis, comparing it to the extravagance and luxury that accompanied the coronation.
Although anti-monarchists are a minority compared to the tens of thousands who rallied on London's streets to support the king, opinion polls suggest that support for the monarchy is declining and at its weakest among young people.
On Saturday, Charles III was crowned king of Britain, amid tight security, in a ceremony that concludes with the inauguration and accession to the throne, and revives ancient royal traditions. Queen Camilla was also erected, but in a simpler ceremony.