More than 50 'dangerous' carbon monoxide alarms have been taken off Amazon and eBay after tests found they did not detect the poisonous gas.

A study from consumer champion Which? found that four models were 'Don't Buys' as they could have led to a toxic build up of CO in homes if used.

Of the models tested by the company, four were found to be "unsafe" - including Amazon's bestseller.

According to Which? another three unbranded alarms were also unable to detect the gas. All three are reported to have been made in China and sold on the websites for less than a tenner.

As well as the models themselves, testers at Which? also found problems with the installation instructions on some of the alarms, which was raised with the websites.

After the test results were shown to Amazon and eBay, the retailers dropped the four alarms from their catalogue and de-listed another 50 that Which? believes are "identical" and could pose a similar risk.

Amazon announced its sellers need to "follow its guidelines" or risk being blocked from selling on the site.

If you are worried about the effectiveness of your carbon monoxide alarm, you can check its safety on the Which? website.