At least 19 environmentalists and six anti-monarchy protesters were detained, including the leader of the Republic republican movement, Graham Smith, as they tried to demonstrate alongside the procession.
At least 19 environmental activists were arrested as they prepared to protest along the route of Saturday's Coronation procession in central London.
They were carried away by police as they shouted messages about climate change and some were wearing T-shirts reading 'Just stop oil'.
Several members of the anti-monarch group Republic, including its leader Graham Smith, were also detained ahead of Saturday's procession. They had planned to hold placards and chant 'Not my king' as the monarch's carriage went past. The group says police were informed in advance of its plans.
But before the procession took place, they were stopped near Trafalgar Square and led to police vans. Others managed to protest along the route, dressed in yellow and waving placards with slogans including “King parasite” and “Abolish the monarchy.”
Police had said they would have a low tolerance for people seeking to disrupt the day but the arrests have sparked widespread criticism that police are stifling free speech.
"This is something you would expect to see in Moscow, not in London," Human Rights Watch said.
The police confirmed that they had made several arrests on suspicion of disturbing the peace in several places.
Although the anti-monarchy movement remains a very small minority, its proportion is growing among the population, particularly among the young. Their presence was unimaginable under Elizabeth II, a sign of the challenges facing Charles III, an already elderly sovereign who is far less popular than his mother or his heir William, 40.
More than 11,000 officers were mobilised in London on Saturday and police have warned that they will be intolerant of those who want to "spoil the celebrations".
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