Drug barons promote heroin in the hunt for fatter profits: US war on narcotics is failing to stop a new 'product' hitting the streets, writes Patrick Cockburn in Washington

HEROIN is increasingly challenging cocaine as America's favourite drug following a shift in the marketing strategy of Latin American drug traffickers. Colombia, says the State Department, 'is the centre of an aggressive effort by the cocaine trafficking organisations to diversify into opium and heroin'.

The switch comes primarily because heroin is more profitable. A kilogram (2.2lb) of cocaine wholesales for between dollars 10,500 ( pounds 7,300) and dollars 40,000 in the United States, while a kilogram of heroin costs dollars 50,000 to dollars 250,000 on the wholesale market, according to the department's annual report on international drugs. It says: 'With the likelihood that heroin will be to the 1990s what cocaine was to the 1980s, Latin American trafficking organisations are poised to cash in on the heroin epidemic.'

Heroin has further advantages for drug traders. Cocaine is a stimulant that burns out consumers in about five years. Heroin is a depressant that can be taken over a much longer period. Opium, the base for heroin, can also be grown more diversely than Andean coca, from which cocaine is made. Currently, 56 per cent of coca comes from Peru, 24 per cent from Bolivia and 20 per cent from Colombia.

The main producers of opium are countries over which the US has little influence, notably Burma, which provides 60 per cent of the opium gum for the US market.

Afghanistan comes a distant second as a supplier, followed by Laos and Pakistan. Latin America is still far behind but Colombian drug dealers are developing new strains of the opium poppy to give a higher yield.

The State Department also pinpoints Nigeria as increasingly critical in the heroin trade. It says: 'Trafficking organisations from Nigeria are becoming the service industry of choice for the heroin trade. Almost every country reporting heroin seizures notes the involvement of Nigerian drug traffickers.'

Last October the US issued a warning to the former Nigerian head of state about the failure of his country's anti- drugs programme. The report says there is evidence of high- level corruption.

Although the State Department seeks to be upbeat about the efforts to combat the international drugs trade, the credibility of the so-called 'War on Drugs' launched by the US in the Eighties is being increasingly called into question. Its aim was to choke the supply of drugs at source.

In the most eloquent attack on this policy, the Attorney- General of Colombia, Gustavo de Greiff, wrote in the Washington Post last month that this policy had demonstrably failed.

'Today, cocaine on the streets of Washington is less expensive than it was in 1980,' he said. 'What is surprising is that it has taken so long for the central fact of the drug trade to sink in - as long as a kilo of cocaine changes in value from dollars 500 to perhaps dollars 20,000 by virtue of the short flight from Colombia to the United States, there will always be people who will be willing to enter the business.'

Mr de Greiff strenuously defended his policy of plea-bargaining with leaders of the Cali cartel in Colombia on the grounds that obtaining hard evidence against them was virtually impossible.

He played down the significance of the death of Pablo Escobar, the founder of the Medellin cartel, killed in a shoot-out in December last year. The Cali cartel was not a cohesive criminal organisation and only a limited amount was known about how it operated, he said. Plea-bargaining with its leaders would gain information about how Colombian drug trafficking now works.

The State Department report makes clear there is no shortage of raw opium or coca. Given that a ton of cocaine is worth dollars 100m to dollars 200m on US streets, the 'drug revenues give trafficking organisations the capacity to buy influence and protection at almost every level of government'.

The State Department cites some instances of official corruption. In January this year the Zambian foreign minister resigned after allegations about drugs, while Costa Rica's ambassador to Poland was arrested with 12kg of heroin in his possession.

As described by Pablo Escobar, the essence of the drugs trade remains: 'You bribe somebody here, you bribe somebody there and you pay a friendly banker to bring the money out of the country.'