THE head of England's leading republican movement has been arrested at an anti-monarchy protest in London.

Footage on Twitter showed five organisers, including Graham Smith, chief executive of the anti-monarchy group Republic, being apprehended by police in St Martin’s Lane, Westminster, on Saturday morning.

Pictures appeared to show demonstrators in yellow “Not My King” T-shirts, including Smith, having their details taken by officers.

The group had been walking behind a rental van full of hundreds of placards when they were stopped by police.

In one video, when asked whether someone should be arrested for peaceful protest in a democracy, an officer says: “I’m not going to get into a conversation about that – they are under arrest, end of.”

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”.

Just Stop Oil protesters appear to have been been arrested on the Mall as well. A large group from the campaign group were seen in handcuffs, and police have cordoned the group off.

The policy won’t affect protests in Scotland, however, as noted by the campaign group Our Republic, who have organised a rally at Calton Hill in Edinburgh from 3pm on Saturday.

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The group tweeted: “In case you were wondering how democracy was doing in this new modern monarchy. A reminder - the new authoritarian protest laws do not apply in Scotland. We have no concerns about similar happening at our rally.”

After the arrests, Republic activist Luke Whiting, 26, told the PA news agency: “Six Republic members have been arrested including the CEO as the demonstration was starting at the edge of Trafalgar Square.

“It is unclear why, potentially it is because one of them was carrying a megaphone.

“It is unclear exactly whether the police are using these new powers and whether they are misusing them to stop protest happening.”

One woman in a Republic T-shirt who was arrested told PA: “We had a delivery of placards ready for the protest and then the tactical support unit questioned us as to how we we had got through the road closures.

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“They questioned whether what we were doing was a delivery.

“They then said they found evidence of means of locking on, of items that could be used to lock on, and they arrested us.”

Officers carried her away from where she had been standing outside a Tesco store.

Two men who appeared to have been part of the same demonstration were carried away by officers into a marked police van.

The policing operation is set to see 11,500 police officers on duty on Saturday.

A statement on the Metropolitan Police’s Twitter account said: “A significant police operation is under way in central London. We have made a number of arrests in the area of Carlton House Terrace.

“The individuals have been held on suspicion of breaching the peace.

“Earlier today we arrested four people in the area of St Martin’s Lane. They were held on suspicion of conspiracy to cause public nuisance. We seized lock-on devices.

“A further three people were arrested in the area of Wellington Arch. They were held on suspicion of possession articles to cause criminal damage.

“There will be further updates later today.”