TESCO has been ordered to make a major Clubcard change after Lidl took the rival to court.
Lidl scored a victory in a High Court fight over the use of a yellow circle logo to highlight its Clubcard Prices in-store.
A judge on Wednesday said, in a ruling, that she had found for Lidl on claims of trademark infringement, passing off and copyright infringement.
Mrs Justice Joanna Smith oversaw a hearing at the High Court in London earlier this year.
Lidl uses a yellow circle in its main logo while Tesco uses a yellow circle logo to promote its Clubcard price promotion.
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Shoppers that are members of Tesco's loyalty scheme get access to cheaper prices on over 8,000 products through its Clubcard Prices incentive.
A Lidl spokesman said after the ruling: "We are pleased that the court has agreed with us."
The discount supermarket took Tesco to court earlier this year after telling the firm refused to change its Clubcard logo.
A Tesco spokeswoman said: "We are surprised and disappointed by the decision today in relation to the claim brought by Lidl against our Clubcard Prices logo.
"This claim brought by Lidl was just about the colour and shape of the Clubcard Prices logo.
"The judge's ruling concluded that there was no deliberate intent on Tesco's part to copy Lidl's trademark. It has no impact on our Clubcard Prices scheme which we will continue to run in exactly the same way. We intend to appeal."
Mrs Justice Smith said Lidl had made allegations of infringement of registered trademark rights in "Lidl's logo devices", passing off and infringement of copyright.
She said Lidl's complaint concerned what it described as the "use by Tesco of an identifier for its Clubcard Prices promotion".
"Essentially, Lidl says that Tesco is seeking deliberately to ride on the coat tails of Lidl's reputation as a 'discounter' supermarket known for the provision of value," said the judge.
"It is Lidl's case that the Clubcard Prices promotion was adopted by Tesco as part of a campaign that was designed to improve Tesco's ability to compete with discounter supermarkets such as Lidl."
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How does the Tesco Clubcard scheme work?
Tesco's Clubcard was launched in 1995 and, like Sainsbury’s, shoppers can earn points as they shop which can then be used to turn into vouchers for money off food or other partner schemes.
Each time you spend £1 in store and online, you get one point when you scan your card or app.
You also get one point for every £2 spent on fuel.
One point equals 1p, so 150 points gets you £1.50, for example.
You'll need a minimum of 150 points to request a voucher.
Once you have enough points, you can turn them into vouchers worth the face value to spend in store at Tesco, or you can triple their worth to spend at reward partners, including restaurants, and on days out.
Last month, shoppers were left furious after Tesco revealed that from June it will be cutting the maximum value of Clubcard rewards for the second time in five years.
From June 14, customers will no longer be able to exchange vouchers for triple their face value – instead they will be worth only double.
Clubcard holders also get cheaper prices on 8,000 products compared to those without the loyalty card through "Clubcard Prices".
These members-only prices can save the average customer £350 a year, according to the supermarket.
