A south Pembrokeshire secondary school has been at the centre of a police drugs operation. Nine students at Tenby's Greenhill School were searched by police on Friday as part of an exercise aimed at preventing and detecting the misuse of controlled drugs on school premises. Two were subsequently arrested on suspicion of possessing controlled drugs and reprimanded by officers. A third pupil, meanwhile, will be interviewed at a later date in relation to an allegation of possession of cannabis. The operation, targeted at individuals who were searched under legislation conferred by the police and criminal evidence act, was launched following concerns expressed by the school authorities who fully supported the action taken. When contacted by the Observer, Greenhill headmaster, Mr. Chris Noble, said it was a "sad, but necessary" operation due to an increasing number of students bringing cannabis onto school premises. "This is something we cannot sit back and ignore," Mr. Noble said. "We collected as much information as possible as to what was happening before approaching the police and they did a thoroughly professional and sympathetic job," he continued. "Out of the students searched, six were found with nothing on them, which I am pleased about, but it is important that we catch those that do bring drugs onto school premises." Inspector Les Clark, of the town's police station, said that since cannabis was reclassified last year, there seemed to be a general misconception that police officers were not enforcing the law with regard to possession. "Cannabis is still an illegal drug and we retain the right to arrest those found in possession," he said. "Young people and vulnerable adults will always be arrested. "The exercise was in response to concerns raised by the school authorities and will be repeated as and when necessary." Insp. Clark also urged parents to explain to youngsters that the misuse of drugs was against the law and placed them at risk in several ways. "One of the most worrying aspects is that the criminals who peddle drugs to our young people will stop at nothing to maximise profits, sometimes by selling Class A drugs such as heroin or cocaine as well," added Insp. Clark.