Watch Bridget Kendall's report

But, reports Bridget Kendall from the US city of Baltimore, a solution to the problem seems no nearer.

In a report on the tactics being adopted in the city's fight against drugs, she says the use of crack cocaine has decreased in many American cities, and with it the incidence of violence.

But although this is cause for some optimism, statistics in Baltimore are not encouraging. Many are still addicted to crack cocaine and heroin.

A drug-free future for the neighbourhood's children remains a distant prospect

The police acknowledge that they cannot arrest their way out of the problem. Apart from anything else, there is not enough room in the prisons. Instead they are trying to clean up communities by evicting the drug dealers.

A former drug detective, Edward Burns, said he believes the problem cannot be treated just as one of law-enforcement.

He says young people, in the absence of other role models, will look on drug dealers as examples to follow. "The man with the money is the dope dealer," he says. "The man with the money is the guy with a gun."