Evidence on the health benefits of adding fluoride to drinking water will be heard by a council watchdog.

Wakefield Council has been advised to consider the move after research showed 40 per cent of five-year-olds and one in five three-year-olds had decayed teeth.

The council’s Caring for our People overview and scrutiny committee will hear a presentation from Public Health England on water fluoridation on Thursday.

Water fluoridation, which was last considered for the district in 2007, has been controversial in some parts of the country, where it met with a backlash from campaigners who said it could be harmful to health.

Betty Rhodes, who chairs the scrutiny committee, said: “It is important to emphasise that the committee is at a very early stage in the process and no immediate decisions are to be taken on this.

“At this point we are simply looking to establishing whether or not the available evidence is of sufficient quality to warrant further investigation.”

Latest research shows that the Wakefield district’s rates of tooth decay are above average, and the problem is more likely to affect people from deprived backgrounds.

Between a quarter and a third of the district’s school children reported drinking fizzy drinks every day, and more than a quarter ate confectionary daily.

Calcium fluoride occurs naturally in most water supplies but falls short of the amount deemed helpful to oral health.

It is artificially added to tap water in a handful of local authority areas in the UK, but in the US around 70 per cent of people drink fluoridated water.