Horizon: A team of scientists analyse the effects of 20 drugs in terms of physical reaction, addictive qualities and effect on society. Reassessing the government's classification system, largely unchanged since the 1970s, they make some startling discoveries. Among the most shocking claims made are that three unclassified substances - alcohol, solvents and tobacco - are more dangerous than several Class A drugs.

Starring:

Bernard Hill, Jack Fortune

Genre:

Documentary