In a written statement, Hilary Benn MP, Secretary of State for the Environment, said: "The clear advice I have received from the Chief Inspector of Drinking Water is that there is no contamination of the water supply.

"However, a precautionary "Boil Water Notice" has been in place since 25 June as a result of a notified increase in risk reported by Anglian Water to the Drinking Water Inspectorate.

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"I am pleased to report that all relevant agencies appear to have worked extremely well together to respond to this notification.

"I understand that Anglian Water are ahead of schedule for returning supplies to normal and will tell customers as soon as is practicable about the lifting of the boil notice."

Anglian Water said: "We implemented a boil notice having detected traces of cryptosporidium.

"This response was entirely based on good practice, the precautionary principle and the best available information at the time. There are many types of cryptosporidium and it takes rigorous testing to be sure of which type is present.

"The health and safety of our customers remains an issue that we are not prepared to compromise on at any time.

"Following exhaustive investigation, we identified and eliminated the source of the Cryptosporidium. We have subsequently cleaned the water treatment works and are now well advanced in flushing out the associated distribution mains and cleaning water towers and reservoirs.

"Preliminary data indicates that the Cryptosporidium oocysts have now been identified as a type that is of low infectivity to man and the risk is therefore significantly reduced.

"However, we await further confirmation and would ask customers in the affected areas to continue to boil their water until they receive the all clear.

"As soon as we and other relevant agencies are confident that customers can use their water supply as normal, we will be advising customers accordingly."

• For the latest on the water situation in Northampton and Daventry see Friday's Chron.