MARK Ronald, lead engineer at Hometree, said: "Carbon monoxide is difficult to detect but can be deadly where there is a general lack of knowledge about the danger and damage it can cause. One in six homes has a dangerous gas appliance with studies suggesting it causes at least 25 deaths every year in England and Wales.

"The sudden cold means many households are turning their heating on having not used it through the summer and autumn which can mean families are at risk from a faulty boiler or inadequate ventilation. This is why it’s so important to check your boiler and, if you’re concerned, speak or organise a video call with a certified gas safe engineer. It will protect your family but could also save you money in the long term.”