UK Health Secretary Alan Johnson has called for fluoride to be added to England's water supplies. His is asking strategic health authorities (SHAs) to compel water companies to add the chemical. At present, only about 10 percent of England's water is fluoridated.

However, critics of the move argue that there may be long term health risks to fluoridation. They have pointed to research indicating possible heightened risks of cancer, infertility and bone fractures. Excess fluoride is also known to be associated with discoloration of the teeth, a condition known as fluorosis.

Johnson argued that fluoridation has been in operation since the 1940s in the U.S. with no ill effect.