§ Dr. CunninghamTo ask the Secretary of State for the Environment if he will list those water authorities that have tested, or are testing, treated water derived from overground or river sources for the presence of cryptosporidia; and how many tests have revealed the presence of cryptosporidia.
§ Mr. Ridley[holding answer 6 April 1989]: This information is not held centrally. I refer the hon. Member to the reply given to the hon. Member for Oxford, East (Mr. Smith) on 5 April 1989 on the presence of cryptosporidia in water supplies in the Oxford area of Thames water authority.