A line of cocaine can be bought for as little as £1 on the street
A major new cocaine trafficking route has developed into the UK through the Balkans, the UN has warned.
It said the amount trafficked through Eastern Europe has increased "dramatically" and has contributed to the low cost of cocaine in the UK.
Cocaine's street price has dropped to almost half what it was 10 years ago and Home Office figures last week showed a line could be bought for £1.
Ministers say the fall is due to many factors, not just increased supply.
Hamid Ghodse, president of UN drug watchdog the International Narcotics Control Board (INCB), blames the fall in price on cocaine's widespread availability.
He said the drug was much cheaper now because there was "plenty of cocaine available", with increased production in South America's main sources - Colombia, Peru and Bolivia.
These producers have switched their smuggling routes from the Caribbean and the North Atlantic to avoid US and British naval patrols, the INCB's annual report says.
The Balkans - traditionally used to smuggle heroin from Afghanistan and Central Asia into western Europe - are now increasingly being used as a supply line to bring cocaine into Europe, the INCB warns.
The watchdog said smugglers are targeting countries with "weak governmental structures that have limited capacity to defend themselves against drug trafficking and its consequences, such as corruption and drug abuse".
The report also warns that stockpiles of cocaine are being built up in West Africa from where it is smuggled into Europe, either directly or via the Balkans.
"The route of transporting for traffickers has become relatively easier and less susceptible to interdiction," Dr Ghodse said.
He added that unless this new route through eastern Europe was restricted, the price of cocaine would continue to fall.
'People are dying'
However, the Home Office disputes this, arguing that the fall in price is due to several factors, not just increased supply.
Former police chief and London mayoral candidate, Brian Paddick, said the key to shutting off supply is cutting out the demand.
He told the BBC: "There will always be a route through for the drugs if there is a demand for it... Even when you see these large seizures of drugs, that's just the tip of the iceberg.
"It's become socially acceptable and we've got to make it socially unacceptable - we did it with drink driving.
He said people snorting cocaine "at dinner parties" had to be made to realise that "people are dying from using cocaine. Mules who are bringing cocaine into the country are swallowing packets that are bursting and they are dying of heart attacks."
Martin Barnes, chief executive of DrugScope, said the charity is seeing more evidence of the harmful effect of cocaine.
He told the BBC: "We are seeing an increase of people mixing cocaine with particularly alcohol and the danger with that is it creates a particularly harmful toxic substance in the body.
"I think the fact we're seeing more evidence of cocaine-related harms in part could be not just due to increased levels of use, but because of different patterns and ways that people will use the drug as well."
The INCB also reports:
- Criminal gangs are posing as fictitious companies to obtain the chemicals needed to manufacture illicit drugs such as amphetamines and ecstasy
- Canada has become a primary source of ecstasy for North America and a significant supplier for Asia
- Poppy cultivation has shrunk in Afghanistan but the country still produces more than 90% of the world's opium
- Illegal online pharmacies are selling pharmaceutical drugs - or counterfeit versions - without prescription.
In November, the UK recorded the highest number of cocaine users in Europe for the fifth year running, according to the European Monitoring Centre for Drugs and Drug Addiction.
COCAINE TRAFFICKING ROUTES INTO EUROPE VIA WEST AFRICA
1. Most of the world's supply of cocaine comes from South America. Venezuela is one of the main departure points for illicit drug consignments leaving the region. Drugs are flown or shipped to West Africa in shipping containers, small boats, or private and commercial aircraft
2. West Africa has become a major hub for smuggling South American cocaine into Europe as British and American anti-drug efforts have curtailed the use of traditional smuggling routes
3. In West Africa the drugs are stockpiled and prepared for transport into Europe by South American, European and local drugs gangs
4. The drugs are smuggled to Europe by shipping container, overland, airfreight or on commercial passenger flights using "mules" via West and East Africa.
The countries shown are identified in the INCB report. Routes shown are general indications of illicit drug routes. They are not intended to show exact routes.
Source: INCB, Interpol