The six basic travel adaptors also presented fire safety concerns in tests.
These included missing safety shutters – which protect people from coming into contact with a plug’s live internal parts – missing fuses and oversized pin holes.
The Office for Product Safety and Standards has noted such concerns when issuing alerts for travel adaptors.
For instance, it recently ordered the recall of one product, external it said lacked safety shutters and rejected the import of another, external, saying it presented a serious risk of fire because it did not meet UK plug dimension requirements.
Online reviews seen by ESF also sparked concerns about how widely the devices it tested may have been purchased and used.
In one review on Amazon Marketplace, a user claimed the device “fell apart in their hands” and they “could have been electrocuted” if this had happened during use.
“We require all products offered in our store to comply with applicable laws, regulations and our own policies,” said an Amazon spokesperson.
“The products identified have been removed from sale.”
They added: “If we discover a product was undetected by our automated checks, we address the issue immediately and refine our controls.”
Meanwhile a review of a universal travel adaptor on AliExpress claimed it exploded while in use.
An AliExpress spokesperson told the it had removed the products flagged by ESF and was contacting affected customers to initiate a recall.
“We have also launched a wider review of universal travel adapter listings where all plug pins are shown extended at the same time,” they said, adding AliExpress would restrict listings with this “unsafe characteristic” until corrected by the seller.
An eBay spokesperson said they “combine technology, AI-supported monitoring and specialist teams to help maintain a safe and trusted marketplace,” adding its efforts have “prevented millions of potentially unsafe items from being listed every year”.
TikTok said it “robustly” enforced it policies, “with 99.5% of the violative products we remove taken down before they are listed”.
But ESF believes the government should do more to hold online sellers to account.
“Shopping in the UK is currently far too dangerous,” said Capanna.
“These platforms claim customer safety is a priority, yet our investigations show that, in reality, they perpetually fail to prevent dangerous goods being made freely available to the public.”
It has called for online marketplaces to be made legally responsible for products sold on their sites, saying this would help protect consumers from dangerous electrical goods.
Consumer group Which? recently said it discovered phone chargers for sale online that posed similar dangers to users, external.
“Badly designed electricals can have life-altering – even fatal – consequences,” said head of consumer protection Sue Davies.
“It’s appalling that online marketplaces continue to fail to prevent dangerous products from reaching consumers, despite countless warnings.”