The BBC's James Westhead on the fluoridisation debate

This is one of the findings in research done by the National Alliance for Equity in Dental Health.

It is calling on the government to extend water fluoridation to reach the 25% of the population where tooth decay rates are unacceptably high.

And it says it is sure its plans are safe.

Previous research has suggested links between too much fluoride and conditions such as Alzheimer's and bone disease.

Current legislation means that more than 60 health authorities are being prevented from fluoridating water supplies as water companies have the power of veto over implementation.

In areas where there is water fluoridation, decay is generally halved, according to the alliance.

But in Britain's poorest non-fluoridated communities children as young as two are suffering from tooth decay.

The figures show that in non-fluoridated inner city areas such as Glasgow, Belfast, Cardiff, Liverpool, Manchester and Inner London as many as 20% of five-year-olds has already had at least one baby tooth extracted because of decay.

By contrast, in areas that have had water fluoridation for 30 years or more, such as Newcastle and Birmingham, only five per cent of five-year-olds have had an extraction.

Pain and trauma

Many water supplies are not fluoridated

Chief Executive of the British Dental Association, John Hunt, said: "Tooth extractions can involve not only pain and trauma, but can also have longer term psychological consequences.

"Tooth extraction under general anaesthetic also carries the risk associated with any general anaesthetic.

"Tooth decay is preventable, and in areas where decay rates are high, water fluoridation would cut disease levels in half. Opinion polls show strong public support for the measure."

In its Green Paper on Public Health, Our Healthier Nation, launched in February 1998, the government stated its intention to review the current impasse over water fluoridation, and said "fluoridation offers an important and effective method of protecting the population from tooth decay".

A government spokeswoman said: "The government is concerned to explore ways of bridging the gap between those who are opposed to any fluoridation of the water supply and those who believe that only in this way can the children most at risk be protected against the damaging effects of tooth decay."

Decay rates fallen dramatically

The level of decay in children's teeth has fallen dramatically in the last 25 years. Since fluoride was first added to toothpaste in the 1970s, tooth decay has reduced by 75%.

Fluoride exists naturally in all water supplies. In some places, such as Hartlepool, fluoride occurs naturally at the optimum level of one part of fluoride per million parts of water.

In most places, where the fluoride concentration is substantially below the optimum level, it can be artificially topped up.

However, only about 10% of the population drink fluoridated water, mainly in the West Midlands and the North East.