Thousands of homes were affected by the accident which contaminated the water supply in Camelford, Cornwall, with a toxic mix of aluminium sulphate and metals.

To mark the anniversary of the incident, a group or residents will call for a full investigation when they meet Tony Blair at Downing Street.

Drinking the water turned many people's hair green

Campaigners will also tie black ribbons around the gates of the water treatment works to remember how in 1988 a relief driver accidentally tipped 20 tonnes of aluminium sulphate into the wrong tank.

The chemical, used to remove solid particles from cloudy water, went directly into the mains supply at Lowermoor Water Treatment Works and on to 20,000 homes.

The company's switchboard was flooded with complaints about dirty, foul tasting water but no warnings were given to the public on the night of the accident despite the acidity in the water flushing out a cocktail of chemicals from the pipe networks as well as lead and copper piping in people's homes.

The contamination had an immediate affect on the Camelford community with residents suffering a range of effects including dyed green hair from copper residues.

In 1994, 148 victims accepted damages totalling almost £400,000 in a settlement approved by a High Court Judge.

But the Lowermoor Support Group, which represents some of those who were affected, is still pressing for a public inquiry.

A decade on many people are still complaining of chronic side effects ranging from short term memory loss, joint pains, lethargy and multiple allergies.

Campaigners who visit the Prime Minister in London will remind Tony Blair that while in opposition in 1989, his party demanded a public inquiry.

Organiser Doreen Skudder said: "We have never ever had the whole thing properly investigated, so we still need a public inquiry.

"Ten years is a long time to wait for justice."

Aluminium Sulphate was tipped into the wrong inlet by a driver

The former water authority - now succeeded by the privatised South West Water - was convicted in 1991 of endangering public health by supplying polluted water, and fined £10,000 and ordered to pay £25,000 costs after a 17-day trial at Exeter Crown Court.

The government has said it is considering evidence to support campaigners' request for a public inquiry.

North Cornwall Liberal Democrat MP Paul Tyler, who is joining the delegation to Downing Street, said: "The effect on the health of the population is still noticeable 10 years on.

"People continue to suffer from the related effects of the toxins yet there is an ongoing denial of any health or social assistance to those victims."

The demand for an inquiry has been supported by scientists who want guidelines drawn up to prevent any similar incident happening in the future.

Cornwall Health Authority is now about to analyse data of deaths of former Camelford residents between 1991 and 1997 but says it does not expect to find any correlation with the incident.