UK government officials relaxed seafood labelling rules last year despite warnings that shoppers looking for mackerel could be misled into buying an entirely different fish. Internal emails show officials at the environment department sought to change the rules "as quickly as we are able" so that a Chilean fish could be legally sold as "jack mackerel".
Chilean jack mackerel belongs to a different family of fish from traditional mackerel and has roughly half as much omega-3. The Financial Times reported in September that much of the canned "mackerel" sold in the UK no longer contained any traditional species, which has become overfished. Some consumers have criticised the inferior taste.
The matter came to a head in 2025, after Princes Group, a major supplier to supermarkets Tesco and J Sainsbury, had already begun selling tins labelled "jack mackerel". In October 2025, a trading standards officer in Cambridgeshire & Peterborough flagged to the Department for Environment, Food & Rural Affairs that a "major brand" had launched a product with packaging that was "potentially ambiguous or confusing", warning of "likely consumer detriment". Princes was told by St Helens Borough Council that the name was acceptable, and later changed its packaging to increase the prominence of the word "Jack".
At the time, Princes was preparing to float on the London Stock Exchange, raising £400mn in an IPO on October 31. Less than a month after internal concerns were raised, Defra published revised rules allowing species from the Trachurus family to be labelled as "jack mackerel". The change was approved by a government working group that included supermarket representatives.
Source: Financial Times Companies · Summarized by HeadlinesBriefing