DON’T scare the horses. Usually it’s a warning issued in jest. Careful now! Don’t cause a scene. Keep any scandalous behaviour in the private domain.

But now the risk of horses being scared has been cited by the Metropolitan Police as justification for arresting three people in the early hours of Saturday morning in Soho on suspicion of conspiracy to commit public nuisance. Among the items seized were “a number of rape alarms”.

Initially, the force tweeted that it had received intelligence indicating that “people were planning to throw rape alarms” to disrupt the King’s coronation procession. It subsequently deleted that claim and instead stated that it believed “people were planning to use rape alarms to disrupt the coronation procession”.

As if it weren’t already concerning enough that possession of rape alarms was being treated this way by, of all forces, the Metropolitan Police, it then emerged that at the time of their arrest, the trio were volunteering as part of a scheme to help women on nights out. Odd that they were out at 2am on Saturday morning, carrying rape alarms as part of their volunteering roles, if they were planning to disrupt the coronation later on the same day.

Westminster’s Night Stars initiative offers “assistance and support to women and those in need or who are vulnerable due to intoxication”, with volunteers wearing pink reflective vests bearing various logos including that of one of its partners: the Metropolitan Police.

It is, of course, debatable whether glimpsing that logo would provide reassurance to a drunk woman alone on the streets in need of help.

Searching for comments in praise of how the coronation weekend was policed, I entered the phrase “Metropolitan Police hailed” into Google. “Did you mean: met police jailed?” it asked, showing me a disturbing array of news stories about criminal policemen: David Carrick, the serial rapist who considered himself “untouchable” due to his job; Liam Boshein, who was jailed after sending a “frankly repulsive” extreme pornographic image to a trainee colleague as “banter”; Thomas Andrews, who assaulted a woman by pushing her to the ground and received both a prison sentence and restraining order; and Sam Grigg, who tied up his female housemate with duct tape and when threatened with being reported said: “Who are you going to tell? I’m the police.”

It remains to be seen what further action, if any, results from the arrests of the Night Stars volunteers, one of whom is a supporter of Extinction Rebellion and had an XR badge on his hat, but the very suggestion that possession of rape alarms might be treated similarly to the possession of super-strength glue, or the bamboo structures used by groups like Extinction Rebellion to create blockades, is alarming indeed.

READ MORE: Dominic Raab's plan to scrap Human Rights Act 'won’t be coming back'

I was struck by one comment on Twitter that dismissed the possibility there might be legitimate reasons to hand out rape alarms on the night before the coronation, “when the streets were full of people camping out, thousands of police on duty and the anti-monarchists thought woman [sic] would be raped”.

Yes, because we all know that spontaneous tent villages are safe havens where no-one is ever harmed, and that women always loudly call out for a nearby police officer when being subjected to sexual assault, never freezing in fear.

Perhaps the tweeter missed the news that a man was last year charged with two counts of sexual assault after allegedly exposing himself and pushing into two women as they all stood in the long queue to see the Queen’s coffin lying in state.

The Mail on Sunday reported last month of “Extremists’ vile plot to spook king’s horses with rape alarms”. Professor Colin Davis, a psychology professor and regular participant in Extinction Rebellion protests, highlights that the story appears to draw a link between this “vile plot” and groups of both environmental activists and republicans. One might think it strange that either of those groups – especially the former – would choose to target animals as part of a protest.

Davis notes that in addition to reporting on the claims about rape alarms from “security sources”, the Mail on Sunday found a tweet from the English Constitution Party, which stated: “Coronation eggs welcome. Bring rape alarms.” He suggests that “quite possibly the claims about plans to throw alarms was a conflation with the eggs”.

The Metropolitan Police announced in advance of last weekend that their “tolerance for disruption” would be low, and that they would “deal robustly with anyone intent on undermining this celebration”. Is it the role of the police to ensure celebrations are not “undermined”? Ensuring public safety is one thing – but it’s unclear how confiscating republican placards contributed to that aim.

Perhaps it will turn out that the late-night volunteering was an ingenious cover story for a plan to startle horses and cause coronation carnage hours later. The alternative – that the police set out to find someone, anyone, carrying rape alarms to arrest – does not bear thinking about.