Metropolitan Police bosses are to be questioned by the London Assembly over the force’s treatment of protesters during this weekend’s coronation celebrations.
A total of 64 people were arrested – including 13 people to “prevent a breach of the peace” and a man with an unused megaphone, who police said could “scare the horses”.
Four people were then charged.
Reports also claimed volunteers who were handing out rape alarms to keep women safe in the early hours of Saturday morning were taken into custody.
Met Police commander Karen Findlay defended the force’s actions, saying officers policed the coronation “proportionately” and within the “context” of the large-scale event.
But opposition politicians and protest groups have raised concerns officers were heavy-handed and impinged on the right to protest.
Speaking to the BBC, chair of the London Assembly’s Police and Crime Committee, Caroline Russell, said members would be questioning senior officers about the operation.
“I think it’s really worrying that these arrests have happened,” added the Green Party leader in the Assembly.
“It felt like for someone who was trying to protest, and trying to do it by the book, it was very difficult to understand what the rules were.”
She also said the reports around volunteers being arrested, who were thought to have been part of Westminster City Council’s Night Stars programme, were “absolutely extraordinary”.
Ms Russell said her committee questions London Mayor Sadiq Khan – who has sought “urgent clarity” around the arrests – and the force every fortnight, “so of course we will be questioning this because I’m sure members of all parties will want to have their questions answered”.
The arrests came after police were given additional powers to tackle disruptive protests through new government legislation just days before the coronation took place.
The change to the law means demonstrators face up to a year in jail for blocking roads, airports and railways, and lets officers stop and search anyone they suspect is planning to cause disruption.
The head of the anti-monarchy campaign group Republic, Graham Smith, said he was arrested before the coronation on Saturday and held in a police cell for 16 hours, despite engagement with the Met for four months over the group’s protest plans.
“The whole thing was a deliberate attempt to disrupt and diminish our protest in order to protect the coronation,” he told the BBC.
“[The Met] has repeatedly said right up until Friday that they had no concerns about our protest plans, they were well aware of what we were going to do and they would engage with us and not disrupt us – so they have repeatedly lied about their intentions and I believe that they had every intention of arresting us prior to doing so.”
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Asked if, within the context of the coronation – where many thousands wanted to attend the event and celebrate – police were right to take action, Mr Smith said: “That is not an excuse to rob people of their rights, that is not an excuse to arrest people and detain them for 16 hours because some people want to enjoy a party, that is a disgraceful suggestion.
“You have to be able to protest and if some people don’t like the fact that there were protesters there then, frankly, they have to put up with it.
“You cannot say that they have to enjoy a party and therefore other people have to be arrested.”
On Sunday, the deputy leader of the Liberal Democrats, Daisy Cooper, told Sky News she had “concerns” the force did not get the balance right when it came to ensuring the event went ahead safely while allowing peaceful protest.
“Whether you are royalist or whether you are republican, we should all be able to agree on free speech and the right to protest,” she added.
But Lucy Frazer, the culture secretary, told Sophy Ridge on Sunday the Met “managed to get that balance right”, while deputy chairman of the Conservative party, Lee Anderson, told those who didn’t approve of the celebrations to “emigrate”.