A London university is offering its students the chance to take part in a study in which they'll be asked to take cocaine.

King's College London (KCL) sent an email to hundreds of undergraduates asking for volunteers to take part in a study which will involve the "nasal administration of cocaine".

The clinical study will look at what effect taking the class A drug has on the body. Those who will be asked to part will not be allowed to cut or highlight their hair for 120 days as part of the investigation into physical effects of the drug.

The email sent to the students warned that those who are already "users of recreational drugs" will not be allowed to take part.

The project, which has been approved by London Westminster Research Ethics Committee, falls under the college's requirement to conduct research and teaching research methods and will be supervised by the clinical toxicology department at St Thomas' Hospital.

Those who take part in the study will be required to give repeated "blood, urine, hair, sweat, oral fluid" samples which will be tested to see how cocaine and metabolites are spread through the body.

The study will consist of one visit where the students will take the drug, followed by at least five more visits during a 90-day period where the samples will be taken.

The students were told in the email: "You are under no obligation to reply to this email, however if you choose to, participation in this research is voluntary and you may withdraw at any time."

A spokesman for King's said: "This is an important scientific study to investigate how cocaine and its metabolites are spread through the human body.

"All the relevant ethical approvals were received for this study. The study will be conducted under the highest level of medical supervision in a dedicated clinical research suite. Further information about the NHS ethical approval process, which was followed, is available on our website."