Thousands of people may be buying imitation Ugg boots made from the pelts of animals skinned alive.
The fur comes from raccoon dogs, a species related to domestic dogs, farmed in China.
A shocking video of the skins being collected has led activists to demand a ban on the trade and call for clearer labeling.
Genuine Ugg boots cost up to $300 and use sheepskin, which is produced in a humane way.
Campaigners from Humane Society International have found that other companies in Australia, where the popular Ugg boots are made, are using raccoon dog fur farmed in China and labeling it “Australian sheepskin”.
HSI campaigners warned that the footwear could have found its way into the UK.
While the UK law says that no products using dog or cat fur may be imported or sold in the country, there is no ban on fur from raccoon dogs, an Asian species with links to foxes, dogs and jackals. They are not related to raccoons.
Wendy Higgins from HSI UK said: “I have been working in animal rights for more than a decade and have never seen a video that has shocked me so much.
“It is not just the killing of the animals that is horrific, but the fact that they must endure such slow, painful deaths.
“These animals are not dogs, so there is no legislative reason why boots containing the fur cannot be imported into the UK. There are also many problems with the labelling of fur products, so many consumers will not be aware of where the fur in their boots comes from.”
Websites found by HSI show other companies are selling the fur on gilets, coats and ear-muffs for delivery to the UK.
Ugg Australia denied they were using the fur in their own boots and pointed the finger at cheap copies.
Lena McDonald from Ugg Australia said the use of raccoon dog fur by other companies was tarnishing the entire industry as many people were unable to tell the different brands apart.
Lena McDonald said her company used its own tannery to ensure the standards of its boots, but added that up to 40 products using fur from overseas contained the word “ugg”.
“As far as I can see many of these boots are not made in Australia at all yet they have the words Australia and ugg on them. We have seen companies cutting off tags saying “made in China” and putting on a <<made in Australia>> tag.”
The UK Government announced its ban on importing cat and dog pelts from China in 2001 after it emerged that a fur collar, obtained from a leading store in the West End, contained dog fur.
A total ban on the trade in dog and cat fur came into force across Europe in December 2008.