Eamonn Butler at the Adam Smith Institute’s blog says:

Naturally, the police, and academics at Britain’s state-funded universities, are fulminating against private security and say it doesn’t cut crime. But would residents fork out £1,000 a year if they thought there was no effect?

Perhaps. But the academic critique of private policing I’m aware of doesn’t focus at all on the instrumental question of its effectiveness. Quite the opposite, actually.

The major concern of some academic critics of private policing is that the authority of private security services is based entirely on enforcing property rights and that they are not accountable to anyone other than those who pay them.

As more and more previously public spaces are being sealed off and privately policed (think hoodie ban at Bluewater shopping centre), more and more public forums are subject to private law (ie “Do as I say or get off my land”) enforced by private police, rather than public law enforced by democratically-accountable authorities and limited by the sort of human rights legislation that civil libertarians ought to be interested in.

The dystopian scenario, expressed by Mike Davis in his study of Los Angeles, City of Quartz, would be a world in which the wealthy live in bubbles of secure, privately-policed gated communities while lobbying to reduce tax funding of the (less effective) public police services everyone else must still rely on.

Now, like every academic debate, there are many critics of this view, which is admittedly over the top. But that’s what theoretical ideal types are for: spotting the essential logic of a particular trend.