The price of cocaine is set to plunge further as traffickers exploit new smuggling routes, an international drugs agency warned.
The International Narcotics Control Board (INCB) said cocaine prices would continue to fall unless action was taken to block supply routes through West Africa and Eastern Europe.
South American drug producers are switching supplies from the Caribbean and North Atlantic to avoid Royal Navy and US authorities, its annual report found.
Stockpiles of the drug are building up in West Africa from where it is shipped to the UK and the rest of Europe either directly or via the Balkans.
Cocaine prices have plummeted in recent years and official figures uncovered last week showed a line of cocaine now costs as little as £1.
Traffickers are loading commercial flights with "large numbers" of drug mules swallowing as much as a kilogram of cocaine each, the report warns. This "shotgun approach" makes it more difficult for police and customs officials to spot every mule.
The report also highlights concerns over cannabis use. The UK tops the European league table of cannabis use by teenagers. Around 44% of 15 to 16-year-olds admit taking the drug, compared to less than 10% in Norway.
But the authors highlight "significant" falls in cannabis use by that age group in England, by around 4% between 2001 and 2007. And they welcome the Government's decision to reclassify cannabis in to Class B because of fears over the impact of strong "skunk" strains on the mental health of young people.
British youngsters are also being targeted by illegal online pharmacies selling heroin substitute, the report warns. The unlicensed pharmacies sell methadone, codeine, and other stimulants without prescription.
The West Africa trafficking route needs to be "urgently addressed", the report states.
