Tesco's 'personalised deal' on sunflower oil cost 6p more than the shelf price

In February 2025, Tesco — the UK's largest supermarket, with over 20 million Clubcard users — launched a trial called 'Your Clubcard Prices,' generating personalised promotional offers via an algorithm built on purchase histories analysed by Dunnhumby, Tesco's data subsidiary. Selected customers received tailored discounts through the Tesco app every Wednesday, valid for seven days.

In July 2026, a Reddit user discovered that their personalised offer for Tesco own-brand one-litre sunflower oil was priced at £1.55 — while the standard shelf price was £1.49. The 'personalised deal' was 6p more expensive than simply buying the product without the offer. The cause: after the personalised offer was generated, the product was added to Tesco's Aldi Price Match scheme, which cut the shelf price below the promotional price. The algorithm did not update.

The glitch landed in the middle of a multi-year Clubcard controversy. In 2023, Tesco moved all special offers to Clubcard-only, creating a two-tier pricing system. Consumer group Which? reported Tesco to the Competition and Markets Authority, alleging the offers lacked transparency. In February 2024, Tesco agreed to add unit pricing to all Clubcard offers. In March 2024, Tesco lost a trademark appeal to Lidl over the Clubcard Prices logo, facing roughly £8 million in rebranding costs.