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The Drinking Water Inspectorate has announced that it will not be prosecuting Three Valleys Water over an outbreak ...
The Drinking Water Inspectorate has announced that it will not be prosecuting Three Valleys Water over an outbreak of cryptosporidiosis in North London in March 1997.

The decision follows the completion of a detailed investigation

by the Inspectorate into the outbreak of cryptosporidiosis which took

place in the north London area in March 1997. The investigation

included careful consideration of whether the outbreak could be

associated with the water supplied from Clay Lane Water Treatment

Works and, in light of the judge's ruling in the Torbay case, whether

a prosecution case should be commenced. It has been decided not to

proceed with a prosecution.

A full report has been prepared which is publicly available. The

detailed recommendations are to be considered by the Expert Group on

Cryptosporidium in Water Supplies, a body set up following this


The Water Company installed in 1997 additional treatment at the

Clay Lane works to remove cryptosporidium oocysts from the water.

Michael Rouse, chief inspector of the Drinking Water Inspectorate, said:

'The inspectorate has reached this decision following a detailed

investigation into the cryptosporidium outbreak in north London, and

careful consideration of whether a successful prosecution could be


'The law as presently interpreted rules out the possibility of

proceeding in the only way which has so far been identified as

reasonably practical. I can understand that the consumers affected

will be disappointed that we are not able to pursue a prosecution.

'It is now important to study the lessons to be learnt from this

case in order to help prevent similar outbreaks from occurring.

'The source water circumstances of this case have not been

observed before and I look forward to seeing the recommendations of

the expert group on any additional safeguards that are considered



1. The inspectorate has investigated the outbreak of

cryptosporidiosis which affected a large number of people in parts of

north London in March last year and its report is available on

request. Detailed recommendations in the report will be considered

by the Expert Group on Cryptosporidium in Water Supplies. This

Expert Group was set up in response to the incident which occurred at

a water works treating ground water sources.

2. In September 1997 the inspectorate initiated a prosecution against

South West Water relating to an incident in 1995 involving an

outbreak of cryptosporidiosis in the Torbay area. At Bristol crown

court the judge, in his discretion, decreed that the Report of the

Outbreak Control Team was inadmissible. This report was part of the

evidence to be presented by the Inspectorate in support of the

prosecution of the company for allegedly supplying water unfit for

human consumption.

3. The inspectorate considers additional powers are necessary in

support of the necessary strong regulation of drinking water quality

in the protection of public health and a consultation document was

issued on 6 May on proposed new regulations for monitoring and

treatment of supplies of highest risk from cryptosporidium.

4. Cryptosporidiosis, which is the illness arising from exposure to

cryptosporidium, is a self limiting condition in most adults,

although unpleasant, and can last for several weeks. However,

infants, the elderly and the immuno-compromised are at greater risk

than the general population.

5. Cryptosporidium is a microscopic parasite found in man and animals

which has been recognised relatively recently as a cause of

diarrhoea. It can be spread by contact with animals and people and

by food and water. Properly operated water treatment processes are

effective in removing it but cannot entirely eliminate the risk.

6. The Drinking Water Inspectorate was set up on 2 January 1990. Its

main task is to check that water companies in England and Wales

supply wholesome water and comply with the requirements of the Water

Quality Regulations.

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