An investigation by the consumer champion found that the online marketplaces are rife with poorly designed and unsafe electrical appliances which could cause electric shocks or start fires.

Which? tested dozens of USB chargers, travel adaptors and power banks listed for sale across the four shopping sites. These were a combination of products that were unbranded or where the brand was unrecognised by Which? experts.

USB chargers

It found that eight of 12 USB charges that claimed to work with Apple products presented an electric shock risk, while seven also failed electrical strength tests.

When researchers tested a USB charger bought from Chinese shopping giant AliExpress, “arcing” could be heard during testing. This indicated that an electric current was flowing through the air and could result in an electric shock, the charger catching fire, or the product being powered exploding.

AliExpress operates a third-party marketplace where individual merchants and manufacturers sell goods directly to consumers.

An AliExpress spokesperson said: “AliExpress considers the safety of all our customers to be of paramount importance. We require our merchants to comply with all applicable local rules and regulations in the markets they sell to. We also prohibit the sale of products in contravention of the product listing policy of AliExpress and we have policies and procedures in place to help us identify listings which infringe the policies of our online marketplace by third party sellers. We will continue to take action against sellers who violate our terms of use.”

Power banks

Four of the nine unknown brand power banks purchased online also failed Which? testing due to a range of faults that could all lead to the products overheating and catching fire.

Of the branded products tested, one power bank made by Trust and purchased from Amazon Marketplace was so poorly put together that it started to smoke and melt during charging.

A spokesperson for Trust told Which?: “Our power banks have all required compliance certificates. If our power banks are used according to the included manual and safety instructions, the power banks should function in a faultless manner. The power bank that you tested appears to be an incidental and exceptional chip failure”

Which? also tested a Go Travel 4000mAh Mobile Power Bank which overheated and caused damage to the case and the circuit board. Go Travel claimed the test result was “an anomaly” but agreed to begin an immediate investigation.

Safety standards

In total, nearly three-quarters of the 33 unbranded or unknown brand products Which? purchased from online marketplaces failed the electrical safety tests. Worryingly, several of the products displayed a CE mark, suggesting to consumers that they are legal to sell in the UK and meet all safety standards.

All four online marketplaces agreed to remove listings of the unsafe items following Which?’s investigation. However, the consumer champion is growing increasingly concerned that the product safety system isn’t equipped to prevent dangerous products from being sold online.

Which? wants to see online marketplaces taking greater responsibility for the products sold on their sites and shut out the unscrupulous operators currently given free rein to sell inferior or dangerous products. It said that the Office for Product Safety & Standards (OPSS) and Trading Standards should also ensure that these sites are more effectively policed.

Natalie Hitchins, Which? head of home products and services, said: “Online marketplaces that list cheap and unsafe electrical products sold by unknown brands are putting people at risk. These products might be cheap but our testing shows they have the potential to cause serious damage or injury, including electric shocks and fires.

“Online marketplaces need to take greater responsibility for the products that are sold on their sites – while the product safety authorities must do much more to identify unsafe products and keep them out of people’s homes.”