If you have an environmental stimulus that enhances the toxicity of a drug which is taken recreationally, I think that makes the research justifiable

Dr Jenny Morton, head researcher

Wendy Higgins, BUAV campaigns director, said: "These sick experiments are absolutely despicable and will shock the public as yet another example of the Home Office rubber stamping experiments that the majority of the British public would find abhorrent.

"Just because people choose to take drugs and go to raves doesn't justify subjecting animals to suffering and death in the laboratory in procedures that will tell us nothing we don't already know - taking drugs and listening to excessively loud music isn't good for you."

But head researcher, Dr Jenny Morton, insisted that the study was fully justified and conducted responsibly.

Inject animals

She said it was part of a wider investigation into the long-term toxic effects of amphetamines, which are still largely unknown.

Dance band The Prodigy was used in experiments

A total of 238 mice were used in the experiment, conducted at Cambridge four years ago - the results were published in August in the journal NeuroReport.

Mice given the drug methamphetamine - a strong form of "speed" taken in clubs - were exposed to silence, white noise, or loud music either by The Prodigy or Bach's Violin Concerto in A minor, which has a similar tempo.

Animals injected with salt water instead of methamphetamine fell asleep when exposed to the music.

'Pulsating noise'

But the sound dramatically affected the drugged mice, causing them to suffer more brain damage from the speed than normal.

Scientists concluded that loud pulsating music seemed to strengthen the toxic effects of methamphetamine in mice.

As well as the seven Prodigy fatalities, four of the 40 mice made to listen to Bach also died.

Dr Morton said on Thursday that the volume used - 95 decibels - was equivalent to listening to a personal stereo turned up reasonably loud.

She added the nature of the music was irrelevant, and said it was the "pulsating noise" that was important.

She said the only other attempt to investigate the effect of noise on amphetamine toxicity was a crude experiment conducted in 1942 which involved the researcher banging a filing cabinet near a group of mice.

Dr Morton said: "Amphetamines are taken recreationally in clubs and by people like truck drivers who expose themselves to loud noise.

"These experiments were done as part of a larger study into the effect of amphetamine on the striatum, a part of the brain which degenerates in Huntingdon's disease.

"If you have an environmental stimulus that enhances the toxicity of a drug which is taken recreationally, I think that makes the research justifiable."

She added: "This experiment was done only once, and we would not have used other animals unnecessarily."