It is Monday morning and time for another routine drug test at a Dublin private secondary school. Mr Murphy holds up a urine specimen jar in front of a group of randomly selected students. "You're next," he says, handing the container to a pale-faced 16-year-old, writes Miriam Donohoe
"Thanks, sir," the fifth-year student whispers as he slouches towards the toilet.
Scenes like this may soon become a common feature of the Irish education system as more secondary schools consider the introduction of random drug testing for pupils.
It emerged this week that two of the country's top fee-paying schools, Sutton Park and St Andrew's, Booterstown, have already introduced random drug testing of students. At least 15 other private schools are reported to be considering following their lead and have sought information from a company which supplies drug-testing kits, Advanced Diagnostic Products.
And the international president of Europe Against Drugs (EURAD), Grainne Kenny, has called for random drug testing in all Dublin secondary schools as a pilot scheme.
Like many things, we will be following the lead of the US where 27 million schoolchildren are facing the prospect of random drug testing following a landmark court case in July.The US Supreme Court ruled that it is legal to extend drug testing, currently common for student athletes, to other pupils. As a result, schools are requiring teenagers to produce urine samples not only to join sports teams but also if they want to join the marching band or the chess club. Hundreds of schools have already begun testing students.
Drug-use among students is a huge problem in this country, especially in middle-class areas. A recent Union of Students of Ireland survey found that one in four Irish students started taking drugs before they were aged 16. Some 14 per cent of students surveyed said they were dependent and needed help to stop.
Yet random testing for drugs in schools is not the answer and is wrong for several reasons. As the mother of a first-year student, I am very uneasy about it, and many parents I have spoken to this week share my concerns.
The pro-drugs testing brigade points to the growing drug problem, especially amongst teenage, middle-class students. They say random testing is justified given the extent and the stubborn nature of adolescent substance abuse.
But have we thought this through properly? For starters, random drug-testing of juveniles is a huge invasion of privacy and may be open to legal challenge. Testing for illegal drugs without reasonable cause is a psychological violation as much as a physical one.
Surely a random drug-testing policy does not make for a good atmosphere in a school and sends a message to students that they are not to be trusted? This is sure to affect the relationship between students, parents and the school authorities.
Placing the burden of conducting drug tests on the schools reinforces what has become a common theme in education over the last 20 years: the notion of school as policer and parent.
Parents for too long have stood by and allowed their responsibilities to be transferred to the classroom. Many schools have already been asked to shoulder the burden in relation to a host of teen issues, such as pregnancy, sex education and mental health. Surely parents should be a major part of the equation? If schools want to help root out drug abuse among students, they would be better employed looking at what leads to drug use.
Drug abuse is much more likely to be discovered by good teachers, who know their students and have open lines of communication with them, rather than through random urinalysis.
Recently we were appalled at the idea that the Catholic Church applied its canon law to clerical sex abuse cases. In doing so it ignored the criminal laws of the State, and did not pass on the name of abusers to gardaí.
In Sutton Park and St Andrew's if a pupil tests positive once they must undergo drug counselling. If they test positive again, they are expelled. There has been no mention of the school authorities bringing in gardaí to investigate where the drugs come from, and of them delivering stern warnings to those who buy and use them.
Drug abuse, no matter what age, is a criminal offence. What gives any school the authority to apply its own set of rules when it comes to drug users? The crimes of sex abuse and drug abuse are vastly different but the principle here is the same.
There is also the issue of class. With counselling and support there is a good chance that the majority of fee-paying students in our private schools will emerge from their teenage drug-taking intact and will go on to forge successful careers in business and the professions.
There's far less chance of this happening for students in public schools in socially deprived areas. It won't be counselling and expulsions that will follow their drug taking but appearances in the local district court on drug-related charges.
Having random drug testing as part of the school system is turning the war on drugs into a war against all teenagers. There are other ways of tackling the problem.