A petition with more than 16,000 signatures demanding a full investigation into the death of a seven-year-old boy was presented to the Environment Agency headquarters.
Zane Gbangbola, a student at St George's College Junior School, Weybridge, died from poisoning by cyanide from toxic water at his home in Chertsey during the flooding of the River Thames earlier this year.
An inquest date has not been set.
His parents, Kye Gbangbola and Nicole Lawler, believe the poisoning was from contaminated water from a landfill site near Chertsey.
Mr Gbangbola, who was paralysed from the waist down due to the hydrogen cyanide poisoning, said "we are starting to believe the causes behind his death are being swept under the carpet".
About 50 supporters, including fashion designer Dame Vivienne Westwood marched from Westminster on Friday, November 28, to hand the petition to the Environment Agency's chief executive Paul Leinster.
June 10, 2014 Carbon monoxide caused death of Zane Gbangbola, tests reveal
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