An undercover investigation by the BBC has lifted the lid on the deadly world of legal highs.

Journalists followed the journey of these dangerous and highly addictive substances from source to sale and used secret filming.

A programme to broadcast on BBC One Scotland at 9pm tonight will look at the growing legal high epidemic, where synthetic drugs are designed to mimic the effects of illegal drugs such as cannabis, ecstasy and cocaine.

Last year the Evening Times revealed that these lethal drugs which can kill are openly sold in shops across Glasgow.

We were able to buy a potentially fatal cocktail of legal highs in under an hour from city shopkeepers who were keen to offer advice about how the drugs should be taken.

We spoke to young people who regularly buy legal highs for pocket money prices and desperate medics who have to deal with the aftermath.

During our series we also interviewed experts on NPS and police officers from the drugs squad who warned they are losing the battle against New Psychoactive Substances (NPS).

The BBC team who produced tonight’s documentary enlisted the help of one of the world’s foremost forensic toxicology firms, Randox Testing Services, to investigate the make-up of these drugs, which contain a cocktail of chemical ingredients that suppliers regularly tweak to evade the law.

Test results show that legal highs contain a poisonous mixture of synthetic cannabinoids which have as strong an effect as illegal drugs, such as LSD or Amphetamines, and in some cases even stronger.

Dr Mark Piper, Head of Toxicology at Randox Testing Services, said: “You don’t know what’s in them and what quantities of chemicals are used, and therefore how much to take. These substances were not even designed to be used on humans, so in taking them you are playing Russian roulette with your life.

“In supporting the fantastic investigative team from the BBC we are glad to assist in highlighting this growing epidemic which has had shattering effects on families and communities across the UK.”