A health authority’s plans for the fluoridation of Southampton’s tap water were not unlawful, the High Court has ruled.

A judge rejected accusations by Southampton resident Geraldine Milner that the decision-making process was “defective”.

Mr Justice Holman, sitting in London, ruled there was no substance in any of the grounds of complaint and the legal challenge must be dismissed. Ms Milner brought her application for judicial review backed by local anti-fluoride campaign groups.

The South Central Strategic Health Authority used statutory powers to instruct Southern Water, the local water provider, to go ahead with fluoridation in February 2009. Other local authorities had put other fluoridation schemes on hold pending the outcome of the case.

Refusing the claim for judicial review, the judge expressed sympathy for people like Ms Milner who disagreed with fluoridation but said he had not been able to conclude that there had been any illegality in the decision-making process.

He said: “I appreciate that that will deeply disappoint Ms Milner and the many objectors in the affected area, to whose position I am sympathetic. However it is important to stress that our democratic Parliament decided long ago that water can, in certain circumstances, be fluoridated.”

Ms Milner’s counsel, David Wolfe, said the health authority decision meant that approximately 195,000 people in Southampton and parts of south west Hampshire “would have fluoride added to their water whether they liked it or not”.

The decision was made even though 72 per cent of those who responded to public consultation opposed fluoridation.

Mr Wolfe accused the local strategic health authority of going against government policy that no new fluoridation schemes should be introduced unless a majority was in favour. On Friday Mr Justice Holman disagreed and ruled that was not the law.

Later the SCSHA welcomed the judge’s ruling, saying in a statement: “The SHA board remains satisfied that water fluoridation is a safe and effective way to improve dental health and will now be considering its next steps.”