The consumer champion found that infrared thermometers sold on popular online marketplaces, including Amazon and eBay, give inaccurate temperature readings, suggesting they have not been adequately checked or safety monitored by the online platforms.

Which? is concerned about the consequences for people using these devices. It pointed out that parents buy them to help check if their babies are ill; while for adults, Covid temperature checks have become a part of everyday life.

Which? bought eight non-contact ‘gun’ style thermometers from AliExpress, Amazon, eBay and Wish, all sold for under £10. It carried out hundreds of temperature checks with them and found that three of the eight were ‘wildly inaccurate’ and could lead users to believe they were hotter than they actually were.

All of the thermometers Which? looked at featured near the top of the online marketplaces’ listings for obvious search terms such as ‘forehead thermometer’.

Two thermometers Which? bought from sellers on eBay and one from Amazon repeatedly failed to provide accurate temperature readings. Which? has named these products as ‘Don’t Buys’ and considers them to be dangerously inaccurate thermometers that consumers should avoid.

This follows a Medicines and Healthcare products Regulatory Agency (MHRA) warning in July this year about an increased rise in the number of inaccurate infrared thermometers making their way onto the UK market, prompted by demand caused by the pandemic.

Seven of the eight products Which? tested, even the ones that provided more accurate temperature readings, were also either missing CE marks completely or the CE marks provided did not comply with the law. These marks are meant to show that the manufacturer has checked that the product meets all safety, health and environmental requirements.

An infrared thermometer, bought from Amazon for £6.37 and with almost 2,000 customer ratings, was the least reliable of the eight thermometers tested. After 44 temperature tests the readings provided were on average 1.5°C hotter than they should have been.

This product was branded as the Aicare A66 on the Amazon listing Which? bought it from. However, upon further investigation – and after contacting the manufacturer of the Aicare A66 – Which? believes the product it tested could be a counterfeit. The instructions were incomplete, key information about how to test the product was missing and the packaging was missing a CE mark.

A KRK non-contact infrared thermometer, bought from eBay for £8.59 was tested 44 times across 11 temperature points and the temperatures given were on average too hot by 0.64°C.

A JK-A007 digital temperature thermometer, bought from eBay for £6.89, also had wildly variable temperature readings. After the initial round of tests, it was delivering results that were more than 1°C hotter than the correct reading.

The online marketplaces said that they had removed the products with issues that were flagged as available on their sites by Which?, seven in total.

Which? believes the government needs to do more to prevent unsafe products being sold online by bringing in tougher laws and regulations to make online marketplaces legally responsible for dangerous products offered through their sites.

Sue Davies, Which? head of consumer protection policy, said: “Consumers should not have to face a lottery when buying a thermometer online, particularly given these products have taken on a greater importance due to the Covid-19 pandemic.

“The government and regulators have recognised the problem of unsafe products sold on online marketplaces but they must take robust action to crack down on this issue now. The government must bring in tougher laws and regulations to make online platforms legally responsible for unsafe products offered through their sites.”