The debate between prohibitionists and drug reformers is often one between morality and pragmatism.

Comments made last week by Bernard Hogan-Howe, Commissioner of the Metropolitan Police, about drug testing employees to deter use, put him firmly in the moral camp. He argued that employers have the right to impose conditions on employees’ lifestyles. Hogan-Howe was essentially underlining his frustration of the failure of possession offences to have any impact on prevalence, by calling for a shift toward sanctions for consumption.

In a speech to the Policy Exchange think tank in London, Hogan-Howe asked the audience rather pejoratively, “How many drug addicts have you got working for you?”

He suggested a huge broadening in the types of employees who should be tested, including teachers and all clinical staff, “if you are trying to affect the demand side of things.”

“What you can do to is start testing in employment, not to tell the police, but as an issue of employment. You say [to your employees], ‘You’ve got a choice; you either change what you’re doing, because I don’t want you working for me anymore.’”

To start with Hogan-Howe is guilty of conflating drug use with addiction. Anyone would agree that someone with a drug dependency is a liability to his employer and his colleagues. But random drug testing of teachers as Hogan-Howe suggests, would also terminate the careers of those who use illicit drugs occasionally with negligible impact on their efficiency in the working week. So in these circumstances, is it useful and is it ethical?

Such a testing regime would be certain to fuel the escalating use of legal highs. There is also the question of discrimination, if all hospital surgeons should be tested, what about their managers too? If testing were to be imposed on an organisation as large as the NHS then cost would be a very significant factor too.

Imposing sanctions on using a drug can lead to highly disproportionate punishments. During a drug conference a couple of years ago I met a senior Indian human rights lawyer. She described how the consumption offence works in India; how police chiefs in various cities raid student parties (invariably with media in tow) and arrest everybody. Then, typically, 3-400 party goers are subject to compulsory drug testing and, if positive, face prosecution. Naturally there are many false positives and justice often depends on your ability to hire a good lawyer. She had several clients who had lost their university places in US and UK, which seemed a heavy price to pay for attending a party.

Of course there has never been a law against consuming a drug in UK, but in the desire to deter use, we should be careful where cod psychology on public behaviour can lead. The Queen’s speech earlier this month included provision to set prescribed limits for controlled drugs for a new drug driving offence. Cannabis stays in the muscle fat for about a month so the draft law will be a “de facto” consumption offence for the most popular drug.

Some professions, where there is a responsibility for public safety, naturally require regular testing such as train and bus drivers. There is no strong moral defence against testing anyone whose impairment would severely risk lives. The Health and Safety Executive, who are responsible for the relevant legislation, stress in their guidance, “This policy should aim to support affected employees rather than punish them… If an employee admits to being a drug user, your policy should seek to help them rather than lead simply to dismissing them.”

Employers may impose testing for more reputational reasons such as the services or police. But there are also a growing number of banks, particularly US based institutions, who insist on drug testing staff. One city worker described how American banks imposed a pre-employment test as a standard part of the contract of employment. However there has been a hardening of opinion on drug use in recent years. When drug problems were revealed, often through arrest, employees no longer hoped for a benign response from the employer and a second chance. Only immediate termination of the contract would be expected.

Drug testing is clearly one of our few booming industries. The typical kinds of firms seeking to impose drug and alcohol testing are construction, transport, manufacturing, police, and utilities. Graham Sievers, Director of Business Development at Concateno, UK’s largest supplier of drug test equipment, said, “We have certainly seen an increase in types of businesses introducing drug and alcohol testing,” and there has been a “30-40 percent increase in interest in our products since last year.”

The ethics of imposing testing regimes regardless of the nature of the job may look shaky but there are areas of testing which are beyond what most would consider morally acceptable. Some companies offer an analysis service where worried parents can drug test their children by removing hair from their combs which is then sent off to a laboratory. Parents who decide they are morally entitled to carry out these non-consensual tests may find family harmony threatened simply by the act of deception.

Hogan-Howe, in his call for extending testing beyond safety critical industries, has revealed his irritation with society behaving in ways he considers morally reprehensible. That’s really not his call. The police regularly prosecuted pop stars and celebrities in the 60s, often by dubious means, because they resented their freewheeling lifestyles.

We should continue to question the merits of a senior policeman’s simplistic moral commentary on drugs as well as guarding against any policy creep toward consumption offences.

Jeremy Sare is parliamentary advisor to the Angelus Foundation