More than a quarter of adults in Britain have taken illegal drugs, according to a survey.

The study for the Observer newspaper, suggests 13 million adults - 28% of the adult population - have used drugs including cannabis and ecstasy.

Watch our interview with the Observer's Robert Yates by clicking the video icon at the top right of this page.

The survey also revealed two million people say they took drugs while under the age of 14 and more than half of 16 to 24-year-olds have tried illegal substances.

Roger Howard, chief executive of Drugscope, said the findings did not surprise him.

Reclassification

"The threat of criminal sanctions is simply not stopping large numbers of young people experimenting with drugs," he told the paper.

The figures come as the government prepares to significantly relax the laws on cannabis.

The paper claims Home Secretary David Blunkett plans to lay fresh legislation before Parliament in June to allow the reclassification of cannabis from Class B to Class C, a move widely seen as effective decriminalisation.

Government officials are quoted as saying two of Mr Blunkett's three "tests" for relaxing the laws have been met.

Lambeth experiment

One hurdle was passed when a report earlier this year from the Advisory Council on the Misuse of Drugs came down in favour of the reclassification of cannabis.

Another was the success of an experiment by police in Lambeth in London, which was well received by the public, under which users have their cannabis seized rather than face prosecution.

The third, as yet unmet test, is the long-awaited Home Affairs Select Committee report on drugs, which the paper says is expected to back the move when it is published next month.

Tobacco risk

The survey of 1,075 adults by ICM for the Observer, weighted to reflect the general adult population, also found that more people now believe tobacco is a "greater risk" than ecstasy.

The survey suggests more than five million people regularly used cannabis, 2.4 million ecstasy and two million amphetamines and cocaine.

Men are twice as likely as women to have taken drugs, with the majority saying cannabis was their drug of choice.

The survey also found that 35% thought cannabis should be decriminalised, 7% said ecstasy should be made legal, but only 4% thought all drugs should be freely available.