The Met said that among the arrests made today were three people suspected of planning to set off rape alarms in an attempt to disrupt the coronation procession.

A Scotland Yard spokesman said they received intelligence on Friday “that indicated groups and individuals seeking to disrupt today’s Coronation proceedings were planning to use and throw rape alarms to disrupt the procession”.

He added: “There was particular concern from military colleagues that this would scare their horses involved in the procession and, as a result, cause significant risk to the safety of the public and the riders.”

Officers arrested three people in Soho at 2am on suspicion of conspiracy to commit public nuisance. Among items seized were a number of rape alarms.

The three people – a 37-year-old woman, a 59-year-old woman and a 47-year-old man – were taken to a south London police station, where they were questioned. The 47-year-old man was also further arrested on suspicion of handling stolen goods.

All three have since been bailed pending further enquiries.

Deputy Assistant Commissioner Ade Adelekan said: “The intelligence we received led us to be extremely worried about the potential risk to public safety. We are aware of and understand there is public concern over these arrests. However, the matter is still under investigation.”

But the Met’s actions were questioned by Westminster councillor Aicha Less, responsible for public protection in the borough, who said she was “concerned” the people arrested may have been members of its Night Stars volunteers group.

She said: “This service has been a familiar and welcome sight in the West End for a long time and have extensive training so they can assist the most vulnerable 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.”

Night Stars is a part of the council’s night safety campaign.

According to the council’s website, Night Star volunteers are “focused on working with the West End’s evening and night-time economy businesses to promote women’s safety and reduce violence against women and girls”.

It adds: “The team will provide wider support to anyone who becomes vulnerable due to intoxication to reduce the risk to their safety or prevent them from becoming victims of crime.

“The Night Safety volunteers aim to make London’s nightlife safer for everyone.

“They provide a welcoming place for all and collaborate to ensure that Westminster’s nightlife remains a safe, inclusive and enjoyable experience for residents and visitors alike.”