A coroner has ruled out poisoning by contaminated cabin air as a factor in the death of a Marlborough airline co-pilot who died believing he had become seriously ill from "aerotoxic sydrome".

The family of Richard Westgate, a co-pilot for British Airways, have claimed that he had suffered from the condition prior to his death in December 2012.

But at the start of an inquest in Salisbury into the death of the 43-year-old, coroner Dr Simon Fox QC said: "Exposure to organophosphate in the course of his employment as a commercial pilot is not a proper issue to be examined by this inquest."

He said the inquest would look at whether Mr Westgate had died from an overdose, intended or not, of the insomnia drug pentobarbital, and whether he had been suffering from myocarditis, an inflammation of the heart muscle.

Mr Westgate died at the Bastion Hotel in Bussum, Netherlands, while undergoing treatment.

His death was initially examined by retired senior coroner for Dorset Sheriff Payne who issued a report in February 2015 which raised concerns that more people could die unless action was taken.

He sent his Regulation 28 report to the chief executive of British Airways and the chief operating officer of the Civil Aviation Authority, both of which are represented at the inquest, as well as the Chief Coroner.

It states: "In my opinion, urgent action should be taken to prevent future deaths and I believe your organisation has the power to take such action."

Mr Payne listed the matters of concern included "occupants of aircraft cabins are exposed to organophosphate compounds with consequential damage to their death".

He added: "That impairment to the health of those controlling aircraft may lead to the death of occupants. There is no real-time monitoring to detect such components in cabin air.

"That no account is taken of genetic variation in the human species such as would render individuals tolerant or intolerant of the exposure."

The Global Cabin Air Quality Executive (GCAQE) says that it is common practice for airlines to use warm, compressed air taken directly from aircraft engines to pressurise the cabin.

Their research suggests that this air, known as "Bleed Air", can become contaminated with engine oils and hydraulic fluids leading to illness among cabin crew through repeated exposure.

The air industry has argued there is no threat to passengers or crew.