The families hiring 'private bobbies' to police their homes

And for some who have employed private security, the presence of guards brings some peace of mind. “I feel an ever so slightly touching of relief that somebody is going to be there,” says Laura.

But what about those who can’t afford a private guard? As David Spencer points out, his own grandmother was burgled, and police took five hours to arrive. “It must have been terrifying for her,” he says.

One angry neighbour shouted at the firm’s boss that this represented an “erosion of the rights of citizens”; another pointed out that guarding services, paid for by the state, have historically been “protected for the public good.”

There have been a few high-profile instances in which private policing has gone awry. One firm in London was set up after three friends were stabbed to death in a park; it made headlines partly due to its controversial methods.

But according to my conversations, most of these “private policing” firms aren’t chasing criminals around. Many are simply employing guards to provide high visibility patrols and to deal with minor incidents (like shouting drunks).

“Most police officers recognise that they can’t be all things to all people,” says Mr Spencer.

He thinks the rise in these firms can’t be regulated away. But there must be a guardrail to ensure that the market is fair – preventing, for example, the buy-up of monopolistic power. “I think if there are more private firms out there then that could potentially help raise confidence in the police, because it would ensure that they’re only dealing with issues that require police intervention.”

Andy Cooke emphasises that police are the only ones who have the legal powers to carry out operational policing. He said in a recent report: “A private security business will never have this power.”

As David Spencer notes, if police have egg on their face because someone has been able to buy better service by going to a private firm, that could accelerate a conversation about where policing should sit.

“This is a kind of pressure valve on the side of the police,” he tells me from his office in central London. “This really should be a wake-up call.”