Police have said they “understand public concern” after officers made 52 arrests throughout the King’s coronation day – including alleged affray, public nuisance and breach-of-the-peace offences.

The Metropolitan Police came under heavy criticism on Saturday after what campaign groups described as “incredibly alarming” detentions during republican protests.

Protesters from the anti-monarchy group, including its chief executive Graham Smith, were apprehended during the day – as well as demonstrators from Just Stop Oil and Animal Rising.

The Met said it received information that protesters were “determined to disrupt” the coronation – including defacing public monuments with paint, breaching barriers and disrupting official movements.

But campaigners said the protests were “peaceful”, describing the arrests as “a dangerous precedent for us as a democratic nation”.

The force confirmed reports from Just Stop Oil that 13 demonstrators were detained on the Mall and six public nuisance arrests on St Martin’s Lane following protests from Republic.

Three people were also apprehended in Soho, three at Wellington Arch and five on Whitehall on conspiracy to cause public nuisance, with another in Whitehall arrested for religiously aggravated behaviour likely to cause harassment.

The Met said a further 14 people were detained in east London on suspicion of conspiracy to cause a public nuisance.

King Charles III coronation
Campaigners labelled the arrests ‘incredibly alarming’ (Labour for a Republic/PA)

All suspects remain in custody, the force said.

Footage from the Mall showed the Just Stop Oil protesters being handcuffed and taken away by a heavy police presence.

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”.

Ms 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.”

Ms 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.”

Human Rights Watch labelled the arrests “incredibly alarming”, adding: “This is something you would expect to see in Moscow, not London.”

Amnesty International’s chief executive Sacha Deshmukh also raised concerns after police were reportedly given instructions to apprehend people with megaphones.

Separately, Westminster Council cabinet member for communities and public protection Aicha Less said she was “deeply concerned” over reports of arrests of members of its Night Star volunteer team, who assist vulnerable people on the streets late at night.

“We are working with the Metropolitan Police to establish exactly what happened, and in the meantime, we are in touch with our volunteers to ensure they are receiving the support they need,” she said.

The Met said they received intelligence that people wanted to disrupt the coronation by using rape alarms to disrupt the procession, and arrested three people in the Soho area on suspicion of conspiracy to commit public nuisance.

Outside London, hundreds of people joined a march through Cardiff city centre in protest against the monarchy as the King was crowned.

Demonstrators walking down Queen Street shouted “Down with the Crown, not my King” and “God save the poor”.

Nick Wall, member of campaign group Republic and chairman of the Labour For Republic organisation, addressed crowds at a Not My King rally in Cardiff where he called the arrests of protesters in London “disgraceful”.

On Wednesday, the Met said it would have an “extremely low threshold” for protests during the coronation celebrations, and that demonstrators could expect “swift action”.

Under the controversial new Public Order Act, protesters who have an object with the intention of using it to “lock on” are liable to a fine, with those who block roads facing 12 months in prison.

Critics previously hit out at plans from the Met to use facial recognition software on crowds to assist their policing operations.