The National Health Service and health secretary Andrew Lansley are suing Reckitt Benckiser for £90 million, following an investigation that ruled the group had abused its dominant position in the UK heartburn market.

The company was slapped with a £10.2 million fine last year after the Office of Fair Trading found it guilty of illegal anti-competitive behaviour relating to its heartburn liquid Gaviscon, following a probe sparked by a BBC Newsnight programme in 2008.

According to the investigation, Reckitt effectively rigged a section of the heartburn market by removing its off-patent Gaviscon Original Liquid from a database used by GPs to search for NHS medicines, so that only the branded and more expensive version - Gaviscon Advance Liquid - would appear available, and thus breaching competition law.

Now the NHS is seeking to recoup some of the losses incurred because of Reckitt's actions. 

Aside from forcing doctors to prescribe its more profitable Gaviscon Advance Liquid, the NHS' suit also claims that the company actively delayed publication, by the British Pharmacopoeia Commission, of what substances make up its product in an attempt to delay copycat versions from entering the market, the Financial Times reports.

The Department of Health said it could not comment the case, but Reckitt said it will "vigorously defend" its position in the case, though added that it could not comment in detail on the content or nature of the government's claim.