Their key complaints are that the incident was never independently investigated, their exposure was never characterised, the local health authority failed to act, and that subsequent official investigations dismissed effects on the health of residents. Their case was taken up by the charity Environmental Assistance, whose report on the incident was presented to Ministers by local Liberal Democrat MP Paul Tyler in 1997.

The issue was brought back into the public eye last October by the publication of long-delayed medical research, led by Dr Paul Altmann, into the health of 55 people exposed during the incident. The group claimed mental impairment as a result of the incident, and the tests confirmed that their symptoms were real (ENDS Report 297, pp 28-32).

Mr Meacher finally responded to the request for an inquiry in December. In a letter to Mr Tyler, he said that the Environmental Assistance report "did not raise any new issues or bring to light any new information which would change the previous view that a public inquiry was not justified." He went on to argue that there had "never been any serious dispute" about the events, and there had since been "a complete change in the organisation and regulation of the water industry."

On the new medical evidence, Mr Meacher said: "I do not believe a public inquiry is the right way to address health issues." Noting that Dr Altmann's study had "not received universal endorsement" from the medical community, he said that the DoH was seeking responses and "would advise the [local] health authority accordingly."

Environmental Assistance was dissatisfied with the response: "The concerns raised in our document have not been answered [neither] does the Government's response answer the need for social justice called for by the victims of the incident." An inquiry is the only way to satisfy public opinion and ensure that lessons have been learned by the authorities, it maintains.

Mr Meacher's letter included 21 pages of "commentary by officials" on the charity's report. It notes that water treatment works are now required to have remote monitoring systems which would raise the alarm in the event of a Camelford-like incident. But Lowermoor was fitted with such an alarm, although its position was such that it could not register the presence of the aluminium.

The commentary also defends the reputation of Dame Barbara Clayton, chairman of an official group which produced two reassuring reports on the health effects of the incident. But it fails to address the charity's assertion that her scientific credibility was compromised by an incident in 1974 when she advised the DoH against accepting emerging evidence of the harmful effects of lead on children's intelligence. The advice turned out to be not only misguided but based on inadequate information.