Selection of 'legal highs' containing Benzylpiperazine (BZP), a recreational drug Wikimedia Commons

Deaths from drug-induced 'legal highs' are on rise in the UK, a new report by UK researchers has revealed.

The number of deaths linked to 'highs' has risen from 10 in 2009 to at least 68 in 2012, registering an increase of over 80% in three years, says a report published in the National Programme on Substance Abuse Deaths (NPSAD), and complied by scientists from St George's, University of London.

And as many as 670,000 young people in the UK are using these 'legal highs', according to estimates by the UN Office on Drug and Crime (UNODC).

Apart from being potentially lethal, these 'highs' - available to buy on the internet and in selected shops around the country - are suspected to cause heart attacks, strokes, organ damage, psychosis and depression.

Professor Fabrizio Schifano, a spokesman for NPSAD, told Sky News that people experimenting with drugs were "effectively dancing in a minefield".

"We have observed an increase in the number and range of these drugs in the post-mortem toxicology results and in the cause of death of cases notified to us," he said.

"These include amphetamine-type substances, dietary supplements, ketamine derivatives, among a host of others.

"The worrying trend is that these type of drugs are showing up more than ever before."

According to the Daily Mail, about a third of the deaths in 2012 were due to a substance chemically similar to the illegal drug mephedrone, also known as 'meow meow' or 'bubbles'.

Others imitated the effects of ketamine and cannabis. Many of the victims of legal highs had taken a cocktail of these drugs along with alcohol.

Legal highs are not tested on humans so the effects of these drugs are not yet known.

"These [NPSAD] figures are truly horrifying: behind each of the 97 deaths is a family torn apart. There are probably hundreds more who suffer life-changing trauma," says Maryon Stewart, founder of drug charity Angelus .

Stewart's 21-year-old medical student daughter Hester died in 2009 after taking a legal high.

About 27 new psychoactive substances or legal highs have been detected by the Home Office's Forensic Early Warning System in the last two years.

The total number of drug-related deaths was 1,613 in 2012, according to the report by NPSAD.

"Clearly this is a major public health concern and we must continue to monitor this worrying development," says Professor Schifano.