A warning has been issued that some Kodi box online streaming devices are a fire hazard.
Electrical Safety First carried out a series of tests on nine types of popular streaming devices entering the UK and found they all failed to meet safety standards.
The Intellectual Property Office estimates that more than one million of the devices have been sold in the UK in the last two years.
In June the EU issued a recall notice for a Chinese-made Android TV box, or Kodi box, amid fears that its poor design left users at risk of electric shock.
The safety warning said the risk of electric shock from the OTT TV Box 4K was 'serious' and advised owners to stop using it immediately.
The devices had faulty power supply units which did not comply with Europe's Low Voltage Directive, meaning users were at risk from touching live components.
Today, Steve Curtler, product safety manager at Electrical Safety First, said: "This year consumers thinking about buying an illegal streaming device for Christmas need to know that by plugging them into their TV they could be potentially be putting themselves, their home and their family at risk.
"We urge anyone with one of these devices to unplug it and stop using it immediately. Not only are these devices breaking the law, but they could be putting your loved ones at risk."
Kieron Sharp, director general of intellectual property protection organisation FACT, which jointly investigated the boxes, said: "Alongside the risks of exposing your home network to damaging malware and your children to inappropriate content, it should now be clear that the dangers these illegal devices pose far outweigh any benefit of buying them.
"We believe hundreds of thousands of illicit streaming devices were sold between Black Friday and Christmas last year.
"This year, if you want to safely and reliably enjoy premium sports, TV or films go directly to the official provider."
Consumers looking for a streaming device are being urged to only buy from a reputable manufacturer and to check the box for the manufacturer's brand name or logo, a model and batch mark number and a safety CE mark.
A Kodi box allows people to stream shows and watch them on a computer, smartphone, tablet or set-top box.
But some boxes are being modified to access paid content channels, illegally allowing people to watch without paying.
Kodi boxes are legal nut become illegal when a box is used to stream subscription channels for free.