LONDON — If you're hoping for a hoverboard this Christmas you may be left disappointed. Thousands of the in-demand motorised self-balancing devices were seized by British authorities at ports and borders because they didn't pass basic safety checks.

See also: Hoverboards in the UK are catching on fire while they charge

More than 17,000 hoverboards imported from outside the European Union have been examined over the past seven weeks, and 15,000 of them didn't make the cut, according to a statement from the National Trading Standards on Thursday.

Many of the seized devices were at risk of exploding or catching fire.

Officers at ports have reported a "huge spike" in the number of hoverboards arriving into the country and large numbers of the items are being sent for testing.

“We suspect that most of these products are being imported for onward sale domestically as Christmas approaches," Chair of the National Trading Standards Toby Harris said. "We urge consumers to be on their guard when purchasing these products."

The national body has released a tip sheet for people who buying hoverboards — telling them to never leave them unattended while charging.

The warning comes weeks after firefighters rushed to a blaze in a bedroom London after a charging hoverboard caught fire. The occupant of the property heard a massive bang and fled after their electric uni-cycle sparked a blaze.

This week in the United States, a man in Alabama posted a video of his hoverboard in flames three days after buying it.