He spreads the contents of his Gladstone bag across the table. There is a kilo of paki black, little bags of skunk seeds, quantities of rock heroin, a spoon, some hubble bubbles, little bottles of poppers, grams of Chinese rock, some ten spots and a few chocolate bars. Some of the bars give off strange smells.

These are the oddly named stock-in-trade of drug dealers and addicts. It's a sad business, says Detective Garda Noel Clarke, as he examines the packages. As a major part of his job in the Garda National Drug Unit (GNDU), Clarke visit schools, hospitals and community centres to brief groups of people on drugs. He talks to parents, students, teachers, community groups and trainee gardai.

"We bring out a certain amount of drugs to show them," he explains. During his talks he explains each item in his bag, what it's worth on the street, how it is used by the addict. He talks about the tell-tale signs of drug abuse, about how to identify drugs with a run-down on what to look for.

People are "exceptionally keen to come and see what it's like," says Clarke. Parents want to be in a postion to deal with it in their own homes and be able to nip it in the bud, he says.

Noel Clarke has been in the force for the past 33 years. He arrived at Templemore, Co Tipperary, as an innocent young lad from Ballymote, Co Sligo. He hoped for a rural posting but fate sent him to Donnybrook Garda Station in Dublin in 1964 - and he has spent all of his working life in the city. aiste Mhuire and finished in 1962. He joined the Garda Siochana two years later. "From the first time I went out on the beat in Donnybrook I loved every moment of it," he says. "I got a different insight into Dublin people - they were always very genuine, the salt of the earth."

After four years he moved to the Special Detective Unit in Dublin Castle in the late Sixties. His work at that time involved protecting and escorting VIPs, working at Aras an Uachtarain and some investigative work into subversive activity.

Later as a detective garda he joined the GNDU, when it was set up in 1972, and was involved in surveillance work, searches and investigations. Yes, he says, this kind of work can be dangerous. "We're dealing with people who, after getting drugs, become down and the euphoric feeling is gone," he explains. "It makes them depressed and angry." Colleagues have been stabbed with syringes, bitten by dogs and beaten up. "But generally the majority of people don't want to cause harm."

Clarke recalls his early days on the drug problem: "When I joined the drug squad the greater percentage of drugs activity was at the top of Stephen's Green. It was mainly young people who came in around town, smoking dope. It was all part of the hippie regime. They were mostly inoffensive people. Cannabis was the most popular drug. There was a very small amount of hard drug users then. They were easy to deal with - they never had any animosity towards the police."

Today, as the longest serving member of the Drug Squad with uninterrupted service since the early Seventies, he can look back and compare that scene with today's crime levels. "In later years a different breed has come along," says Clarke. "They've made fortunes out of the misery of others. They don't mind who they hurt."

His saddest memory was discovering the body of Garda Michael Reynolds, who had been shot, in St Anne's Park, Raheny. "I knew him. We were often on patrol at the same time. We'd always stop and have a chat. He was an excellent policeman. That is one of the down parts."

In comparison to the Nineties, he says, "you hadn't the type or amount of crime that you have nowadays." He takes up an ordinary looking can of brushless shaving foam to demonstrate the deviousness of today's drug dealers - the can has a false bottom where substances are hidden.

Noel Clarke has seen the terrible destruction and death that drugs cause but "a feeling that you're doing something worthwhile" has sustained him. In 1994 he was awarded a Divisional Merit Award for "his caring attitude and humane approach to drug addicts and their families. "There were failures, but it's great to see someone get motivated and go to get treatment. We wanted them to do something with their lives, not to end up in the gutter."