As many as half the illegal drugs seized on the island in recent years proved difficult to identify, as unknown synthetic replicas are superseding traditional stimulants such as cocaine and ecstasy, The Sunday Times of Malta has learnt.

Godwin Sammut, the drug expert who for 17 years has conducted chemical analyses on the bulk of narcotics discovered by the authorities, said chemicals which replicated the effects of popular party substances were becoming increasingly common.

More than two new drugs are being discovered across Europe every week.

“As the world of synthetic drugs grows, new substances are being seized, making identification increasingly difficult. This trend has increased from about two or three years ago and is continuing to increase with the development of even more new drugs.

“At least 40 to 50 per cent of the drugs I see require extensive work to properly identify them,” said Mr Sammut, who is a university chemistry lecturer.

According to the European Union’s drug monitoring agency, for which Mr Sammut compiles annual reports on local findings, more than two new drugs are being discovered across Europe every week.

The number of previously unknown substances identified in the EU has leapt from less than 10 in 2006 to more than 100 by 2014.

Mr Sammut said the synthetic copycat drugs were largely produced in China and mimicked the effects of stimulants such as methylenedioxymethamphetamine (MDMA), the active ingredient in ecstasy pills.