Some of the UK’s biggest branded suppliers plan to take legal action against “free-riding” supermarkets after new evidence emerged to prove copycat own-label products are damaging their brands, The Grocer can reveal.

Research from behavioural science company Mountainview Learning - commissioned by the British Brands Group - showed consumers were slower to recognise brands when they sat alongside very similar supermarket alternatives.

These own label offerings caused “consumers to make errors, mistakenly selecting the copycat brand in place of the established brands,” it added. “We’re talking to a number of leading brands,” said Mountainview’s Dr Jane Leighton, who is partnering with law firm Speechly Bircham on a legal challenge to own-label. “There is a particularly strong interest from US brands,” she added.

Previous challenges under UK intellectual property law, such as Diageo’s successful action against Sainsbury’s over its own-label Pimm’s alternative Pitchers, have been rare because of the perceived lack of evidence of the impact on consumers.

Alex Carter-Silk, a partner at Speechly Bircham, said supermarkets had been “free riding” on brand investment and the research would give judges “powerful” new evidence on which to act.

Products highlighted in the study included Tesco Pro-tech, an own-label rival to GSK’s Sensodyne toothpaste, Asda’s You’d butter Believe It, a rival to Unilever’s I Can’t Believe It’s Not Butter, and Asda Blue Charge, which resembles Red Bull, and Boots’ anti-dandruff shampoo - consistently confused for P&G’s Head and Shoulders.

The BBG is calling on the government, the OFT and Trading Standards to toughen their stance.