A "very high reading" of a toxic gas in a partially redacted report by the Environment Agency was read out aloud in an inquest, fuelling theories that the death of a seven-year-old schoolboy may have been caused by hydrogen cyanide poisoning.

From June 2014: Carbon monoxide caused death of Zane Gbangbola, tests reveal

From Oct 2015: Family of 7-year-old who died in last year's flood will not get a special inquest into his death rules coroner

From Oct 2015: Truth about Zane? Campaigners claim Weybridge schoolboy Zane Gbangbola's death is being covered up by council

Zane Gbangbola, a pupil at St George’s Junior School in Weybridge, suffered a cardiac arrest at his home in Chertsey after floodwaters entered his family’s basement on February 8, 2014 during Surrey's floods.

The family maintain poisonous gases from a former landfill site nearby contaminated the floodwaters, causing their son’s death.

Kye Gbangbola, Zane’s father, also lost the use of his legs after the flooding - something he attributes to the effects of hydrogen cyanide poisoning.

At a pre-inquest review into Zane’s death at Woking Coroner’s Court on Monday, December 7, Lesley Thomas QC, representing the Gbangbola family, read aloud parts of an Environment Agency report during the inquest.

He had also represented the West Yorkshire family of Bobbi and Christi Shepherd who died from toxic gas inhalation from a faulty boiler at the Louis Corcyra Beach Hotel in Corfu in 2006 following negligence by Thomas Cook.

Mr Thomas read from the Environment Agency’s National Incident Recording System report that some information in the document was to be "vetted" not to be "in the public domain".

Mr Thomas said he suspected the report "had been redacted".

Mr Harris, representing the Environment Agency, said that this had been a "formatting error" and that they "had not sought to withhold any information" from the court.

Mr Thomas read on that when the fire service entered the house in February last year after the family was taken to hospital, a gas reading of 25,000 parts per million was taken, showing "high levels of hydrogen cyanide in the upstairs bedroom".

Another recording taken downstairs had the reading 10,000 parts per million, the inquest heard.

At a previous pre-inquest review into Zane’s death, it was said that only one reading of 10 parts per million had been recorded in the house following the evacuation.

Mr Thomas said: "This report says there was more than one reading.

"It’s a very high reading. I don’t think we’ve had an indication that the hydrogen cyanide was ever so high.

"This is the first time that this has come out."

He told coroner Richard Travers: "This is an indication that there well may be evidence that we have not seen.

"You need to satisfy yourself that that documentation is not relevant to this inquest. At this point you can’t say so as you haven’t seen the documentation."

Agreeing that the information should be made public to the court, Mr Travers announced a further pre-inquest review date for December 22 ahead of the inquest in January to allow all parties time to read the document.

A spokeswoman from Spelthorne Council previously denied any wrongdoing on the council’s part in regard to the former landfill site.

She said: "Whilst we have the utmost sympathy for the family’s ongoing anguish, we have always maintained that there is no evidence of a link between the landfill and this tragedy, or of a public health risk.

"We hope that the inquest scheduled for January 2016 will provide the family with the answers they have been rightly seeking about the cause of their son’s death."

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