The prince - who is now strongly opposed to smoking - made the disclosure to primary school pupils in Ljubljana during his official visit to Slovenia.

Prince Charles was greeted as he began his visit by a schoolgirl, Petra Pavic

The confession came after Charles asked pupils whether they had ever tried smoking.

About half of the 28 pupils taking part in the seminar with him at the Martin Krpan School said they had.

"I gave up smoking at the age of 11," said Prince Charles.

"I had one or two strong ones behind the chicken run at school. The good thing is to give them up when you are young."

The Slovenian pupils, told what the prince had said by a translator, burst into laughter.

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Blaz Bhaklar, 11, said he had read that US President Bill Clinton had tried smoking marijuana.

The prince replied: "Don't believe everything you read in the newspapers."

Prince Charles would have been at Cheam school in Berkshire at the time he was talking about. He hinted that in trying cigarettes he had bowed to peer pressure from his classmates.

Damage warning

His comments came in the context of a strong anti-drugs message.

"I have been involved in many organisations with young children about drugs," said the prince.

"Despite all the pressure from young friends and people of the same age, it's tempting to try them - but not worth it in the end," he said.

"I have seen so many damaged people in my own country and all over the world. Some people can handle it but not many.

"You often hear of drug addicts who have been rehabilitated, and go on to help people get away from drugs," he said.

"There's a great discussion whether you should legalise drugs or not, but these ex-drug takers I have talked to all say: 'Never legalise it'."

Common experience

Responding to the prince's comments in the UK, the Director of the anti-smoking group Ash, Clive Bates, said the prince had had what was a very common experience for many children.

"It shows that despite all his privilege and wealth he was still lured into smoking when he was very young," he said.

Mr Bates called on Prince Charles to ban the royal crest from the packets of certain brands of cigarette.

"This ... is a big problem, especially in developing countries where the royals are so highly thought of," he said.

"It effectively shows the royal family promoting cigarettes and giving them a badge of respectability and approval."

But campaigners for the freedom to smoke Forest used the prince's 'do as I say, not as I did' message to claim that cigarettes were not addictive.

Their spokeswoman Juliette Wallbridge said: "It shows people can give up if they want to, and therefore they should have the freedom of choice."

Free cigarettes for students

Meanwhile anti-smoking campaigners in the Irish republic have protested at a plan to hand out free cigarettes at a university ball.

The function, organised by law students at Dublin's University College, promised a night of "free drink, free cigarettes, free cigars and free love".

Up to 5,000 cigarettes - donated by an unnamed tobacco company - are to be handed out to the 350 ballgoers on Tuesday night.

The university's Law Society Auditor, Andrew Fitzpatrick, said: "The vast majority of students are aware of the consequences of smoking, but it has to be said that many of them do smoke.

"And we believe that is their right to choose whether to smoke or not."

But Barry Dempsey, of the Irish Cancer Society, said: "Cigarette smoking is the most preventable cause of cancer. In those circumstances, I do not think the free distribution of cigarettes can be regarded as being in the interests of student welfare.