Keith Allen has defended a forthcoming Channel 4 programme in which he is seen under the influence of drugs and said it is "insane" to suggest it glamorises their use.

The actor has been filmed after taking an ecstasy-like Class A drug to examine the effects.

The experiment has drawn some criticism, with one think-tank boss calling it "reckless and pointless".

But Keith - father of singer Lily - said the programme was designed as a "forensic analysis" investigating drugs. He was among a number of participants who underwent medical monitoring during the course of the trial, for which he took MDMA.

Speaking on ITV1's This Morning, he said: "If you think that I'm glamorising the taking of drugs by spending an hour and 20 minutes for two consecutive Mondays in an MRI scanning machine then you're insane.

"There were policemen taking part. There were definitely soldiers, people who'd never taken it before. It's a very, very forensic analysis, a neurological analysis of the effects of MDMA. It's a form of ecstasy."

He went on: "It led to a debate on Channel 4 with the police, with Government ministers. It's a very forensic analysis and a very calm look at the question of legality and illegality of drugs."

News of the Channel 4 programme drew some condemnation when it emerged yesterday. Julia Manning, chief executive of independent think-tank 2020 Health said: "The first two words that come to mind are reckless and pointless. We are fully aware of the effects of class A drugs on the body."

Keith also talked about releasing a single - under the name Fit Les - protesting about the "corporatisation" of the Olympics.

He said of the track, called The Official Fit Les Olympic Anthem: "A recent poll showed 56% of the people aren't satisfied with the way that it's been presented, the sponsors have got hold of these Games and kind of hijacked them and put us lot on the back burner."