The company behind Trunki suitcases has lost a Supreme Court battle with a rival over the design of children's ride-on luggage.
Magmatic took PMS International, which sells Kiddee Case products, back to court on appeal last year, arguing Kiddee Cases that were decorated as animals or insects infringed its patents and they should be blocked from UK sale.
In a reserved judgment, five Supreme Court justices ruled in favour of PMS - a decision Trunki's founder said would bring a "wave of uncertainty for designers across Britain" as courts in other EU nations had taken a more robust approach to protection.
Rob Law told Sky News: "We created an original product in Trunki and protected it by computer generated registered design – a process used to protect a third of designs across Europe.
"In my honest opinion, the Trunki was wilfully ripped off.
"We stood up to this behaviour, held it to account and took our case all the way to the highest court in the land – only for the judges to rule that we are not protected against the copy.
"They’re effectively sending knights into battle without armour."
The judgment ends a three-year court battle in which the two rivals could not even agree where PMS was based - in Hong Kong or Essex as PMS insisted.
The firm denied its products were a rip-off of Trunki - insisting it had come up with the idea of children's cases for the discount market.
Kiddee Case founder Paul Beverley said the ruling was a "victory for fair competition".
He said: "It upholds the right of consumers to be able to choose competitively-priced products.
"We try always to work within the law and successive courts have agreed that there is no way our popular Kiddee Case can be mistaken for any other product.
"In reality we are operating in very different markets from our rivals and we have never been competing for the same customer base."