CAMPAIGNERS opposed to water fluoridation are to protest in Huddersfield.
Supporters of the Yellow Card campaign, organised by the National Pure Water Association (NPWA) and The Green Party, will be at the Piazza shopping arcade on February 14.
They will talk to the public and ask people to sign the NPWA's national register of people opposed to fluoridation.
Recent Yellow Card rallies in Leeds and Barnsley have boosted signatures on the register to more than 500,000. Further campaign days are planned in Yorkshire.
The campaign aims to give water companies a warning - or yellow card - that customers will take action if water supplies are fluoridated.
Since 1989, most suppliers have not fluoridated water because of consumer objections.
But last November, Parliament gave health authorities powers to order water companies to fluoridate supplies.
Health authorities will have to consult local people first - and they are likely to get a mixed reaction.
Those in favour, including the British Dental Association, say fluoridation would cut tooth decay in children by up to 15%.
But those against fear it could cause brittle bones, discoloured teeth and even cancer.
They also say fluoridating a water supply takes away an individual's choice.
Peter Crampton, spokesman for West Yorkshire Campaign Against Fluoridation, said: "The new law purports to give powers to strategic health authorities to order water companies to add poisonous chemicals to drinking water,
"Water companies say they'll have to obey the health authorities. But we say they have a responsibility to respect the human rights of customers."
He said Yellow Card supporters were targeting Yorkshire Water. Protesters will all write to the company, asking for assurances that water supplies will not be fluoridated.
Yorkshire Water has not yet been ordered to fluoridate its supply, as West Yorkshire Strategic Health Authority is waiting for Government guidance on the new powers.
But the Yellow Card letter says that if the company does fluoridate supplies, campaigning customers will deduct the cost of buying bottled water or de-fluoridation equipment from their bill and only pay what is left.
Some water companies have threatened court action against customers who do this.
A Yorkshire Water spokes- woman said: "The issues of non-payment of bills and water fluoridation are two completely separate things.
"However, we do pursue people for non-payment of bills."