Doped lab mice find Prodigy fatal
Seven mice forced to listen to Prodigy after taking a strong form of amphetamine or "speed" died while others suffered brain damage.
Animal rights campaigners were outraged by the research, described by the British Union for the Abolition of Vivisection (BUAV) as "tasteless and horrific".
Yesterday, a year after the results were first published in the journal NeuroReport, the Home Office confirmed it had taken "infringement action" against the Cambridge University team led by Dr Jenny Morton.
Although the Home Office would not discuss the nature of the action it later emerged that the scientists had received "formal admonitions" and been reminded of the rules under which animal research must be conducted.
The BUAV said it was appalled that the researchers had got away with a "slap on the wrist".
Campaigns director Wendy Higgins said: "It's disgusting. They should be prosecuted for animal cruelty. Why should they get special treatment just because they are scientists?
"There needs to be a completely independent inquiry into the whole business of regulating animal experiments."
The mouse study was a "by-product" of research into Huntingdon's disease for which the Cambridge scientists had obtained an animal experiment licence, the Home Office said.
A total of 238 mice were used, half of which were injected with the drug methamphetamine and half salt water.
The drugged mice were then exposed to silence, white noise a "rushing" sound made from a combination of different frequencies or loud music. The music played was either from dance act The Prodigy or Bach's Violin Concerto in A Minor, both of which have a similar tempo.
Animals injected with salt fell asleep when the music was played.
But the sound dramatically affected the drugged mice, causing them to suffer more speed-induced brain damagethan normal.
They appeared to "jiggle backwards and forwards" as the music pounded in their ears.
As well as the Prodigy fatalities, four mice made to listen to Bach also died.
Dr Morton later insisted the study was fully justified and conducted responsibly. The experiment was part of a wider study looking at the affect of amphetamine on a the striatum, a brain region which degenerates in Huntingdon's disease.
The findings suggested that loud pulsating noise the kind young people are subjected to in clubs could enhance the drug's toxic effects.
Dr Morton said the volume used, 95 decibels, was equivalent to listening to a personal stereo turned up reasonably loud.
The BUAV said it had pursued the matter with the Home Office for nine months.
A Home Office spokeswoman said: "This report was thoroughly investigated by the Animals Inspectorate and appropriate infringement action has been taken.
"The music and drugs study was a by-product of the Huntingdon's disease research. It developed into a separate piece of work which went beyond the procedures authorised by the original project licence."
In May, the BUAV accused Cambridge University of carrying out "horrific" experiments on monkeys without proper authorisation.
Video footage secretly shot during a BUAV undercover operation showed marmosets having their skulls opened and their brains tampered with. The Home Office said it was considering the evidence.
Ms Higgins said Cambridge should be banned from further animal experiments while an independent investigation is carried out.
She said: "The whole relationship between the Home Office and researchers is far too cosy.
"Mice have just as much ability to suffer as dogs, cats or guinea pigs. The scientists deliberately brain damaged and killed these animals, and all they got was a ticking-off.
"This experiment was illegal and totally disregarded the real concerns millions of people have about the regulation of animal research. It shows the contempt the Government has for people who care about animal suffering.''
