A quirky practice designed to reduce dental decay in primary school children inspired by a Hampshire Farmer, Edgar Borrow, in 1971.  It was to be an alternative to fluoridating entire communities and suited those local authorities who were reluctant to propose the  controversial water fluoridation measure.  Since 1971, several developing countries have also adopted the dental milk programme.

"Milk fluoridation has grown since the first community based scheme was introduced in Bulgaria in 1988. By 2000 programmes were operating in five countries and included over 114,000 children. More recently, particularly due to the expansion of the schemes in Thailand and Chile, this figure has increased to over 800,000."  ( Banoczy, J. et al (2009). Milk Fluoridation for the prevention of dental caries.  Geneva.  World Health Organisation. ISBN 978 92 4 1547758.   https://tinyurl.com/mr3pzfmn  .)

During the following 40 years several local authorities in England were persuaded by the Borrow Foundation and Public Health Directors to adopt the practice.  All have since stopped although Blackpool Borough, which came late to the table in November 2016, continues to this day.

Each carton of semi-skimmed milk provided to the children of consenting parents was converted into "dental" milk by the diary by the addition of sodium fluoride.  The children drink the milk 5 days a week but not during school holidays.  Parents were also advised to stop giving them fluoride tablets.

It seems that Blackpool's dental milk programme is an "opt out" scheme. That is, parents need to proactively withhold their permission.  If they somehow fail to do this, following a notification from the school, their child will be automatically enrolled in the programme. 

 ( https://tinyurl.com/4anuzmnu )

This article explores the issue further.