Revealed: How health chiefs plan to put fluoride in half our water supply to halt tooth decay

Dental health chiefs want to add the chemical to 40 per cent of England's water supply to combat high levels of tooth decay.

But critics said the 'mass medication' of water without the population's consent was an invasion of their human rights.

Concerns: Fluoride has been linked to a range of diseases

They also accused dentists of being in denial about the dangers of fluoride, which has been linked to diseases including brittle bones and cancer.

Dental experts, however, said there is overwhelming evidence that adding fluoride to water helps reduce tooth decay, with children the biggest beneficiaries.

Fluoride, which is tasteless and odourless, occurs naturally but is also found in drinking water supplies  -  usually at levels too low to affect dental health.

At present, only 10 per cent of tap water has fluoride added  -  in the West Midlands and the North East.

Although plans to add the chemical to more of the nation's water supply were first announced by Health Secretary Alan Johnson in February, the scale of the Government's intentions has remained under wraps until now. 

In an interview with Dental Tribune magazine, chief dental officer Barry Cockcroft said: 'We only need to fluoridate 40 per cent of the country. Greater Manchester is currently considering it and there are many other areas that are looking at it.'

But he dismissed the ' scaremongering that says it causes cancer'.

'A total of 170million people in America drink fluoridated water and it is the most litigious country in the world,' he said.

But Peter Mansfield, a Lincolnshire-based GP and expert on the effects of fluoride, said: 'It does work a little bit, but nothing like as much as dentists say it does, and it causes as much damage as it does good.

'You are robbing Peter to pay Paul. It is a very flawed science.'

Caroline Lucas, of the Green Party, said the European Convention on Human Rights states individuals have the right not to be medicated without their consent.

The party is taking legal advice on a possible challenge.

She said: 'Putting fluoride in everyone's water amounts to mass medication, which would contravene human rights and medical ethics.'

The Government,which has earmarked £42million to pay for the scheme, has agreed to pick up the costs of any legal claims.

The Department of Health said water companies would only start fluoridating water following consultation with local people.