Nearly half of England’s drinking water could have fluoride added to it under a 'secret' Government plan. Although plans to add the chemical to more of the nation's water supply were announced in February, the scale of the Government's intentions has remained under wraps until now.

Dental health chiefs want to add the chemical to 40 percent of England's water supply to combat high levels of tooth decay. Critics have said that the 'mass medication' of water without the population's consent is an invasion of their rights.

Fluoride has been linked to diseases including brittle bones and cancer. At present, only 10 percent of England’s tap water has fluoride added.