The illegal drugs trade in Britain is bouncing back against tough action by police and customs with seizures failing to curb demand or supply at street level, new research suggests.
The UK Drug Policy Commission report found the £5.3 billion drugs market was proving "extremely resilient" to crackdowns by law enforcement agencies, despite hundreds of millions of pounds spent each year on tackling the problem.
It claims even significant drug seizures and high-profile convictions of traffickers and dealers usually fail to have an impact on supply and demand due to the scale of the market and its ability to adapt quickly to disruptions.
For example, in times of short supply dealers often reduce purity, it said.
The number of Class A drug seizures in England and Wales more than doubled between 1996 and 2005, according to the report.
However, an estimated 60 per cent to 80 per cent of drugs would need to be seized regularly to put major traffickers out of business, even though seizure rates on this scale have never been achieved in the UK or elsewhere.
Tim McSweeney, one of the report authors, said: "Within the research literature there is a consistent call for a better understanding of how drug markets operate and the role that enforcement can have in reducing the damage caused by them.
"We were struck by just how little evidence there is to show that the hundreds of millions of pounds spent on UK enforcement each year has made a sustainable impact and represents value for money."
The report calls for more to be done to reduce the effect of drugs on communities, for instance, by tackling drugs-related "collateral damage" such as gang violence and prostitution.
The authors argue this would have a greater impact on the drugs trade than big hauls.
David Blakey CBE QPM, of the UK Drug Policy Commission, said: "All enforcement agencies aim to reduce drug harms and most have formed local partnerships to do this, but they still tend to be judged by measures of traditional supply-side activity such as seizure rates.
"This is a pity as it is very difficult to show that increasing drug seizures actually leads to less drug-related harm. Of course, drug dealers must be brought to justice, but we should recognise and encourage the wider role that the police and other law enforcement officials can play in reducing the impact of drug markets on our communities."
The report said Britain's illicit drugs market is regarded as one of the most lucrative in the world, worth an estimated £5.3 billion - equivalent to around 33 per cent of the UK tobacco market and 41 per cent of the alcohol market.
Crack and heroin account for about half the expenditure on drugs.
The report said the Government channelled £380 million in 2005/06 in England towards reducing supply.
It added the broader criminal justice costs arising from Class A drug use are estimated to be over £4 billion.
:: The UK Drug Policy Commission is an independent organisation established to provide analysis of drugs policy.