The first known death from a drug popular with clubbers has emerged the day the government banned it.

Toxicologists in London found that a 25-year-old man died hours after taking GBL on its own while out clubbing.

Writing in the Journal of the Royal Society of Medicine, they said the man was found unconscious by his partner who had tried to resuscitate him.

The drug is among a list of so-called "legal highs" banned on Wednesday amid growing evidence of their harm.

The report in the journal details how the man had been previously fit and healthy - but had returned home from a night out in 2008 "acting strangely".

When the ambulance arrived, the crew continued attempts to resuscitate the man. There were further attempts to revive him when he reached hospital, but he died from a prolonged cardiac arrest.

Writing before the ban came into force, the team said that the man's post-mortem revealed the presence of GBL in his body - but no sign of alcohol or any other drug.

Once in the body, chemical reactions turn GBL into another drug, GHB, which has been banned since 2003.

The post-mortem found that the quantity of GBL in the man's body was consistent with the amount seen in previous fatal overdoses involving GHB.