Reckitt Benckiser’s plans to delay a generic version of Gaviscon are nothing new in the pharmaceutical industry.

“Evergreening”, as the process is known, is an accepted part of a drug company’s armoury: a process by which patented drugs are tweaked and then re-patented in a bid to stop generic firms producing much cheaper versions for general sale.

Regulators have recently launched a crackdown on firms who try to hold up the production of generic versions of medicines.

In 2005 AstraZeneca, the Anglo-Swedish drug manufacturer, was fined €60 million for trying to delay its rivals the opportunity to manufacture its ulcer drug Losec, thereby keeping prices artificially high.

And in January the European Commission launched a wide ranging inquiry to determine whether pharmaceutical firms were employing illegal delaying tactics.

The EC raided the offices of some of the world’s largest pharma firms, including Pfizer, GlaxoSmithKline, Astrazeneca, Johnson & Johnson, Merck & Co and Sanofi-Aventis.

Neelie Kroes, the Competition Commissioner, said at the time: "If innovative products are not being produced, and cheaper generic alternatives to existing products are in some cases being delayed, then we need to find out why and, if necessary, take action."

But it is a difficult battle to fight. “They all do their very best to try to delay things,” said one regulatory source. “Because, by law, they don’t have to hand over their recipe book they can do all sorts of silly things like Reckitt have tried. In the end it's a long process anyway, and they want to make it longer.”

Times Recommends

• Lies and cover-up at MG Rover exposed by report
• High oil prices push manufacturing costs up
• Primark founder steps down as chief executive