Carbon Monoxide (CO) is a tasteless, odourless gas that kills. It is produced by the incomplete combustion of fuels like coal and petrol.

Just breathing in small amounts can prove fatal, yet many people still seem unaware of its dangers.

Sadly, it takes a tragedy to remind us all just how lethal CO can be.

Last November, Elizabeth Watkins, 86, a widowed pensioner, was found dead at her home in Severn Road, Chilton.

An inquest on Thursday heard how Mrs Watkins, who cleaned the coal boiler herself, had refused to pay for a service which would have cleared up a decade’s worth of ash deposits blocking the flue.

As a consequence, Mrs Watkins died of CO poisoning.

Giving a ruling of accidental death at Oxfordshire Coroner’s Court, coroner Darren Salter said: “I think it is important for people to have boilers serviced regularly and for people to understand [the difference between] what is cleaning the boiler and what is servicing, which is clearly important and needs to be done by an accredited gas engineer”.

The boiler had last been seen by engineers from Steventon firm F Church in June 2012 and according to service manager Peter Johnson: “We tried to help her out but she liked to do everything herself. That meant we didn’t find the blockage.

“If you’re burning solid fuel it’s no different than putting a portable barbecue in a tent, but you’re allowed to do it.”

So if you are in any way concerned or know of someone who might be at risk, call an engineer. It’s better to be safe than sorry.