I believe Carbon Monoxide detectors should be mandatory just like smoke detectors are in every household in the UK.
Why is this important?
Along with smoke detectors, they are to prevent unnecessary death and possible destruction in any household that catches fire. However, unlike smoke, which at least you can smell and see, carbon monoxide is known as the silent killer as it is harder to be humanly detected and kills on average 30 people a year with unexplained deaths also linked to the deadly gas.