The controversial experiment in the south London borough of Lambeth which saw a "softly, softly" approach to the possession of cannabis ends at midnight Wednesday.

Police say from Thursday 1 August people openly smoking the drug in public face arrest.

Scotland Yard says the experiment has been successful with officers' time being freed to concentrate on the fight against hard drugs.

But critics say it has led to more users and dealers being drawn into Lambeth from other boroughs.

'Aggravating circumstances'

For the past year, Lambeth police have been employing a policy of seizing cannabis and issuing formal warnings to people found in possession of small amounts of it for personal use.

That will continue but police are warning that cannabis is still illegal and people will be arrested if there are "aggravating circumstances" - in line with national policy.

It has been argued that there has been public confusion over drugs policy following Home Secretary David Blunkett's announcement that cannabis will be reclassified from Class B to Class C.

Aggravating circumstances

public disorder openly smoking cannabis in public person under 17 caught in possession

More than 1,000 people have been warned for possession since the scheme began last July.

Of those, 52.7% were from outside the borough, a similar proportion to those caught in possession before the pilot, suggesting people were not flooding into the area to buy drugs, said police.

The change coincides with a survey which suggests more than half of British adult voters do not support the relaxation of penalties for cannabis possession.

A Guardian/ICM poll found only 38% approved of the policy.

But there was a clear age divide, with 54% of those aged 18 to 35 and 55% of 25 to 30-year-olds saying they approved of the change.

The majority (54%) of people aged 35 to 64 disapproved, with 76% of the over 65s also opposed.