It's estimated that there have been more than a hundred raids during the last year, seizing cannabis plants with a street value of millions of pounds.

Drugs Consultant Liam Watson told Week In Week Out:

"Ten years ago, the amount of cannabis that was consumed in Wales that was actually grown in this country, was somewhere between say, five per cent and ten per cent. We have now got a situation in 2OO7 where that figure has risen to 6O per cent, six zero per cent, so we have actually got a situation now where the majority of cannabis that is now consumed in Wales is actually grown in Wales."

And it's being used by more children and young people than ever:

"The numbers of under l6s using cannabis have increased quite dramatically over the last decade." he told the programme.

According to Home Office figures, a third of all children in the UK under the age of sixteen have tried cannabis and they see it as no big deal.

Tom Davies, from Haverfordwest, started smoking cannabis when he was 13 years old. He told Week in Week Out:

"It became the norm after a while. It just became socially acceptable with the people I was with and, well, it just became part of my life."

He warned that cannabis is easily accessible to children:

"Everyone needs to be aware that it is everywhere, it is very easy to get your hands on these days. I don't smoke it any more, but I know from still looking around me that it's everywhere like, I would say 99% of people have come across it once in their school life".

Many cannabis plants have been selectively bred resulting in a much stronger drug, called super skunk. The main active ingredient THC (tetrahydrocannabinol) is up to six times higher in skunk than cannabis resin.

Head boy Matthew White was a Grade A student with a promising future ahead of him. Aged 16, he started smoking skunk. His mum, Colette White, told Week In Week Out how it led to a big change in his personality:

"I don't know what happened. He didn't use to miss school, he completed his GCSEs, he got fantastic results and we were so proud of him," she said.

"And it only took from then which is about May, June, until the October, for it all to unravel. And his life sort of unravelled in all sorts of ways, all his previous ambition disappeared."

In January, weeks after his 18th birthday, Matthew was partying with his friends in Leckwith woods where they lived in a make-shift camp. After smoking skunk all day and taking acid for the first time it's believed Matthew attempted to hang himself. Hours later he did it again.

Colette told Week In Week Out that lessons can be learned from Matthew's death:

"For people to be aware of the damage that can be done just by just smoking cannabis, just that one spliff, just that first one. It may not all end up the way Matthew ended up, but the damage they are dong along the way can be just life changing, it could affect the rest of their lives, the psychiatric impact is huge."

Younger people run a higher risk of developing mental health problems after smoking skunk and about a quarter of the population are genetically predisposed to severe psychological side effects after taking it.

Tom told the programme how skunk affected him:

"I started to close off from my friends, and keep myself indoors and I would still be smoking though, but after a time, it really did still get me seriously paranoid like."

Although cannabis is generally seen as a soft drug Tom says the risks are very real:

"It can't kill you really, it can make you kill yourself and you can hear voices and cause schizophrenia and all that. In the long term, I think it can be worse than LSD and ecstasy and psychological drugs like that".

Paul Flynn, MP for Newport West has been campaigning to de-criminalise cannabis. He said the solution is to treat users as patients instead of criminals:

"We are at the moment trying the impossible in playing this game of believing that the criminal justice system can solve the drug problem."

"Every government since 1971 has believed it, everything they've done has failed, and we've had this increasing toll of wasted lives, of deaths, worse than anywhere in Europe, and we've got to say to the politicians, for goodness sake, be a little courageous, don't go for the easy headline or the quick vote."

"But do what you know is right which is to follow other countries in the harm reduction, that will save lives."

Colette White feels that drugs education needs to start at a young age. She said:

"It's got to be education, at what age would you begin and who's going to take any notice of that when they're that age, when they're young, it's like us warning them about smoking and alcohol, I'm not sure whether the message would get through. But I think that's where it's got to start."

Three years ago the government changed the classification of cannabis from a class B to a class C drug.

That means it's still illegal to possess cannabis to smoke it in public or to sell it but since 2004 anyone found with a small quantity of cannabis for their own personal use is likely to be let off with a caution. And many feel this is sending the wrong message to youngsters.

DAN 24/7 is an all-Wales, 24 hour, bilingual, drug and alcohol helpline.
Call for free help and advice: 0800 633 5588