Here's a reply from Bristol Water yesterday - although it will be the Health Authority making the decision it is reassuring to read this:
Bristol Water's position on fluoridation is unchanged: We do not add fluoride to our supplies, nor do we want to do so. We would have to abide by the law if we were instructed to fluoridate by the local health authorities. However, I am unaware of any such approach being made or planned.
If we became aware of any such move, we would ensure that the Consumer Council for Water was kept informed. As regards the possibility of a fluoridating agent from the Midlands entering our water supply via the water we abstract at Purton, I am told that this is very unlikely, given the huge dilution effect involved.