EUROPEAN patients, taxpayers and national treasuries are being fleeced of billions of euros because of the big pharmaceutical companies' elaborate campaigns to delay the marketing of cheaper generic drugs, the European Commission says.

"There is something rotten in the state [of the pharmaceutical industry]," said Neelie Kroes, the Competition Commissioner, unveiling the findings of an 18-month inquiry. "Makers of original medicines are actively trying to delay the entry of generic medicines on to their markets."

Ms Kroes announced a formal investigation of the French company Les Laboratoires Servier for allegedly stifling competition for the heart disease drug Perindopril and she is believed to be on the brink of ordering another three investigations, including one into practices at GlaxoSmithKline.

A key tactic was for big firms to abuse patenting practices to play for time and wreck the chances of generics firms being able to compete, the commission found.

A common practice was to file a large number of patent applications across European Union states for a single drug - as many as 1300 - in what are known as "patent clusters". Another common option was for the big firms to sue generics companies and then stall the cases in court for several years.