A leading doctor has advised the Government to consider decriminalising drugs as he thinks the blanket ban has failed to cut crime or improve health.
The call comes as chief police officers report a doubling in cases of homegrown cannabis.
A report by the Association of Chief Police Officers (Acpo) said the amount of cannabis being grown in the UK is at its highest ever level.
Commander Allan Gibson, Acpo's lead on tackling cannabis cultivation, told Sky News pressure must remain on drug growers.
"This is organised crime, it's getting invovled in what they see is lucrative business," he said.
"We need to make sure the risks to them are great - that they're being found out and they're crops are being taken away from them, but also the risk of going to prison and having their assets taken away from them."
But Professor Sir Ian Gilmore, a former president of the Royal College of Physicians, said drug laws should be "reconsidered with a view to decriminalising illicit drugs use".
He told Sky News: "The problem is that this policy we have had for 40 years of saying that we do not want drugs in society just isn't working.
"We cannot stop production from overseas and we cannot stop importation, but we can start treating heroin addiction as a medical condition.
"We see people in hospitals every day who are suffering not from heroin but from dirty needles, from impure supplies of the drug.
"It improves health, it gets them off of heroin and it stops the crime, it stops them stealing to feed the habit.""There has been some really successful projects providing, not every addict, but the hard end of the spectrum - so to speak - with clean heroin under controlled conditions.
Sir Ian conceded decriminalisation was a "difficult word" but added he was in favour of looking at a regulatory framework for illicit drugs rather than blanket prohibition.
Similar calls for reform of the UK's drugs laws last month were criticised by some politicians and campaigners.
Keith Vaz, chairman of the House of Commons Home Affairs Select Committee, said the legalisation of drugs "would simply create the mistaken impression that these substances are not harmful, when in fact this is far from the truth".
Sir Ian said: "I don't think anybody thinks heroin is not harmful - far from it."
The doctor added that evidence showed decriminalising heroin or other drugs "doesn't increase the number of drug users".
The aim was one of "helping people with addiction problems, rather than putting them in prison".
Nicholas Green QC, chairman of the UK Bar Council, said: "A growing body of comparative evidence suggests that decriminalising personal use can have positive consequences.
"It can free up huge amounts of police resources, reduce crime and recidivism and improve public health.
"All this can be achieved without any overall increase in drug usage. If this is so, then it would be rational to follow suit."
The Acpo report found in just two years, the number of homegrown cannabis production bases has doubled.
They were most common in urban areas such asManchester, Birmingham andLondon - but West Yorkshire is where the most factories have been found.
Figures for 2009/10 showed 896 illegal commercial growing sites were found in the West Yorkshire Policearea, compared to 368 in 2007/08.
The Acop report suggests the reasons behind the surge are twofold.
Firstly, more organised gangs are opening up new premises and secondly, there is better police detection.
Ordinary-looking homes are used by criminals, but research also shows industrial and commercial premises along with farm buildings are now being used to grow cannabis.
The drug was reclassified from class C to class B in 2009, the publicity led to better awareness in communities and in turn led to police receiving more intelligence from the public.
Commander Gibson said: "There's no complacency here. We recognise it's now spread to all force areas in the United Kingdom.
"We're going to keep our foot on the pedal and we're going to make sure we gather the best intelligence.
"We want to make sure we not just closing down the gardeners but the people behind them.
"We're getting better at covert operations targetting them so they need to realise they are not safe in this business."
Last month, former drugs adviser Professor David Nutt said the UK needed a radical new approach to drugs laws, which may include the regulated sale of some substances.
He added that he believed the criminal approach to drugs has failed spectacularly.
However, there was a reluctance to change because most politicians were scared of losing votes if they were to tell the truth about the failed drug policy.
Professor Nutt was fired by the Labour government after saying ecstasy was less harmful than alcohol.
A Home Office spokesman said: "Drugs such as heroin, cocaine and cannabis are extremely harmful and can cause misery to communities across the country.
"The Government does not believe that decriminalisation is the right approach.
"Our priorities are clear: we want to reduce drug use, crack down on drug-related crime and disorder and help addicts come off drugs for good."