Police in London have followed the lead of their counterparts in Norwich and Loughborough by forming a partnership with nightclub owners to breathalyse customers on the door. This initiative has been criticised for combining the infantilisation of the nanny state with the intrusiveness of Big Brother. And so it does, but few have commented on its most objectionable aspect, which is that it is a shameless piece of rent-seeking. It is a straightforward example of corporate interests working with the state to enrich themselves at the expense of their customers and competition.

One of the ostensible justifications for the scheme is that breathalysers (provided by the state) will provide useful evidence to doormen when they are trying to convince belligerent drunks that they are too inebriated to come in. This is unconvincing. Bouncers are big boys and can look after themselves (that is the point of them). If they say you’re not coming in, you’re not coming in.

A more candid justification for the measure is that it is intended to clamp down on ‘pre-loading’, the perfectly legal act of drinking alcohol in one’s own home before going out. The licensed trade dislikes pre-loading because customers arrive later and drink less. The temperance lobby, which now operates under the guise of ‘public health’, dislikes it because it allows people to drink cheaper alcohol bought from supermarkets. And so, in a classic bootleggers-and-baptists alliance, these traditional foes have found common cause in spreading the belief that the off-trade is responsible for alcohol-related problems which occur in and around the on-trade. The police have now been co-opted into a scheme devised by operators in the nighttime economy to take business from their competitors in the off-trade.

There is an unmistakeable whiff of hypocrisy in the licensed trade’s pious condemnation of so-called ‘pre-loading’. Their complaint is that people are tipsy when they arrive and plastered when they leave, and that the blame lies on those who made them tipsy rather than those who pushed them over the brink. But insofar as a business can be held responsible for its customers’ behaviour, it is surely the person who served them their last drink who is more culpable than those who served them their first.

No one seriously believes that nightclub owners object to people getting drunk on a Friday or Saturday night. Imagine how these licensees would squeal if it was suggested that customers be breathalysed inside their premises every few hours, with those who exceed a benchmark of inebriation being ejected by orders of the police. The real objection of pub and club owners is not to people getting drunk, but to people getting drunk elsewhere, arriving half-cut and needing relatively little further refreshment. They stand to profit enormously from a de facto ban on pre-loading. The question is whether the police should be helping them.

The police are not entirely hapless dupes in this. Some of them doubtless believe that late-night policing will be made easier if patrons come into town stone cold sober. And yet it is surely more likely that customers will make up for lost time by drinking more inside the club. This is not mere conjecture. It is clearly what the pubs and clubs hope and expect. Why else would they be collaborating with the police if they did not think it would lead to more sales?

The breathalysing scheme remains voluntary for now, but it is not difficult to see how it could become mandatory given time. Evidence could be found or concocted to show that participating venues have benefited from less alcohol-related violence, or that problems have been displaced from venues which uses breathalysers to those which do not. Either way, it will be argued that a ‘level playing field’ should be created in which all venues adopt this ‘evidence-based policy’, and since some venues refuse to take part, a little compulsion is necessary. At first, it might be suggested that new licences can only be approved if proprietors take part in the ‘voluntary’ scheme. Once this principle has been established, campaigners will complain about the ‘loophole’ that exempts older venues. Local byelaws and national legislation will be proposed as the ‘next logical step’.

In a slight twist on Adam Smith’s famous line, this will result in an industry which offers merriment and diversion forming a conspiracy against the public. When corporate interests collude with the state, it is the ordinary consumer who pays the price. In this instance, weekend revellers must either pay more, drink less or stay home. They will lose out financially, or be denied their first order preference, or both.

Nightclubs have an obvious incentive for wanting customers to be thirsty on arrival, but if they wish to make blood-alcohol levels a criteria for entry, they should buy their own breathalysers and police it themselves. The state should not be lending its apparatus to private interests to pursue financial rewards.