Earlier this year, the government introduced legislation banning the production, distribution, sale and supply of legal highs. Designed to stop what has been described as a tsunami of chemicals flooding into the UK, it has resulted in the closure of the high street shops which had been selling exotically named substances like Spice, Mamba and China White.

So why are they still finding their way onto the streets? File on 4 traces the supply back to labs in China and discovers a myriad of psychoactive substances are still only a few internet clicks away. Prior to the ban, the authorities were aware of the risk that internet sales could take over from the high street and that China is fast becoming the 'chemical and pharmaceutical wholesaler to the world'.

So is the new legislation really the answer, and if not, what options remain to disrupt the now illegal supply of these lethal substances?

Reporter: Danny Vincent
Producer: Nicola Dowling.