The High Court has rejected an appeal against the Advertising Standards Authority (ASA) after it ruled a campaign claiming "Ribena Toothkind did not encourage tooth decay" was misleading.

The ASA's director general, Christopher Graham said: " I am delighted that the court has upheld our adjudication. The ASA has been vindicated and this judgement acknowledges that we conduct ourselves in a thorough and professional manner."

GlaxoSmithKline, manufacturers of Ribena Toothkind appealed to the High Court following a ruling by the ASA that required the statement "Ribena Toothkind did not encourage tooth decay" to be deleted because it was absolute and not comparative.

In its adjudication, made in July 2000, the ASA also asked the advertisers not to repeat a poster advertisement showing Ribena Toothkind bottles as bristles on a toothbrush, because without a qualifying statement it implied that the product actively benefited oral health.

The High Court appeal was the last possible chance GlaxoSmithKline had to get the ASA decision overturned.

In his judgement the Hon. Mr Justice Hunt rejected a claim that an expert adviser employed by the ASA was biased against GlaxoSmithKline. He also rejected the argument that the ASA did not give proper weight to the British Dental Association, which had accredited the product.

He also said that the advertising codes were "entirely consistent" with Article 10 of the European Convention for the Protection of Human Rights and so rejected the claim that the ASA had unnecessarily restricted free speech.

Neil McCrae, spokesman for GlaxoSmithKline told "Obviously we are very disappointed by the outcome. The court was being asked to look at the way the ASA arrived at its decision and not the science behind the product.

GlaxoSmithKline released a statement saying: "The product has the support of over 1,200 pages of scientific evidence and its claims have been accredited by the British Dental Association (BDA), the UK's leading experts in dental health.

"Within this last week this accreditation has been renewed following a detailed three-yearly review of the scientific data by the BDA's accreditation panel. A move that demonstrates continued support for a product that is widely regarded as a significant step forward for oral health."

The company also welcomes a statement from the Hounslow branch of Trading Standards that it remains entirely convinced by the weight of scientific date behind Ribena Toothkind's claim and has no intention of asking them to remove the claim from its packaging, despite today's ruling.

Following the court's decision GlaxoSmithKline is to consider all legal options and will decide whether or not to appeal in due course.