Water company Three Valleys is to blame for 1997's cryptosporidium bug outbreak in the borough, according to a report released last week.

Released by the Drinking Water Inspectorate (DWI), the report compiled evidence showing that the bug originated in Three Valleys' Bushey treatment works.

Cryptosporidium, a parasite carried by contaminated water, causes severe stomach cramps and diarrhoea. The outbreak in March last year led to 349 diagnosed cases across north London. Children under five, the elderly or those with weakened immune systems were most severely affected.

But there will be no prosecution, despite an incident management team's findings that the outbreak was connected to unboiled water "unfit for human consumption" from Clay Lane treatment works. This is because a similar case in 1995 against South West Water collapsed due to insufficient evidence.

Three Valleys Water issued notices to 325,000 houses instructing them to boil water for drinking, washing teeth and cooking last March. The notices were in force for two weeks and £10 compensation was later issued to every affected household.

But many who were ill are still fighting for more. "Why are they chickening out?" asked one Edgware resident who wished to remain anonymous and who is pursuing a case against the company. "I felt the effects of it for nearly a month. My doctor said it would be OK to go on holiday.

"I went abroad and was ill for the whole ten days. If my family weren't with me I'd have ended up in hospital."

The company has since treated its pumping station in line with guidelines. And the DWI has made more recommendations on water quality monitoring, emergency procedures and risk assessment of ground water sources.

Similar guidelines have gone out to all water companies. Three Valleys Water director Jim McGown said: "There are many constructive recommendations in the report which have been or are being carried out by the company."

The report found:

Deficiencies in Three Valleys' water source risk classification

Inappropriate treatment at Clay Lane treatment works in Bushey

Deficient monitoring provisions of raw water sources feeding Clay Lane

A minimum of 24 hours delay in issuing advice to boil water to households

Lack of information on location of potentially affected properties

Not fully implementing all recommendations of two reports by cryptosporidium experts and inadequate notification of relevant bodies.

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