Law enforcement has "little adverse effect" on the availability of drugs in Britain, new research claims.

A report from the UK Drugs Policy Commission published yesterday said drug markets were "extremely resilient. They are highly fluid and adapt to law enforcement interventions".

The commission, a charity made up of specialists in drug treatment, public policy, policing and medical research, said attempts to tackle Britain's £5.3bn drug habit were not working

Download the new Independent Premium app Sharing the full story, not just the headlines

Tim McSweeney of King's College London, the report's author, said: "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." In 2003/04 the cost of detecting, prosecuting and sentencing class-A drug crime in the UK was £4bn.

The report said enforcement "can have a significant and unintended negative impact on the nature and extent of harms associated with drugs".

A spokesman for the Home Office said that many of the report's recommendations had already been taken up.