Morrisons’ rearguard decision to allow its farmers to use GM feed looks spectacularly ill-informed and dumb given Carrefour labels its own-brand meat and dairy products as GM animal feed-free, or ‘Nourri sans OGM’. If the world’s second-largest retailer can give customers the field-to-fork, GM-free guarantee they clearly and consistently demand, then Morrisons can too.

Morrisons’ misguided policy brings it into line with Asda, which as the UK base for Wal-Mart, unsurprisingly backs GM - the US is home to Big Biotech, renowned for its dogged efforts to force GM down the global gullet.

Morrisons lazily trots out the Monsanto/Cargill line that GM-free animal feed is hard to source, but as Carrefour’s policy shows, this is nonsense. Ricardo de Sousa, boss of the Brazilian Association of non-GM producers, recently reported that a quarter of Brazilian soya-growing land is now cultivated within the ‘soja livre’ (GM-free) scheme.

What’s more, Brazilian growers are finding non-GM soya cultivars more profitable than GM equivalents. They deliver higher yields, farmers are not obliged to pay royalties, and less pesticide is needed.

The truth is GM now looks like old-hat technology. It’s is being superseded by marker-assisted selection (non-GM genetic mapping), which is widely expected to boost yields more effectively than GM, and without the associated risks.

Asda and Morrisons can expect customers to desert in droves to more switched-on rivals when the inevitable food scare around GM feed hits the headlines. Twelve independent research studies on GM have raised animal health issues with theoretical consequences for humans. Lesions in stomachs of Danish pigs fed GM is just the latest health concern.

Ultimately, progressive retailers need to go further than giving customers a GM feed-free guarantee and actively encourage farmers to feed animals on alternative UK-grown crops, such as high-protein peas, field beans and lupin, and rear more farm animals on grass. To build Britain’s food security, we need to cut risky dependence on imported soya and move to sustainable home-grown alternatives.