The amount of lamb with UK-origin labelling in Tesco stores in Britain in July 2017 was down by 15%, compared with the same period last year, according to a survey by the Agriculture and Horticulture Development Board.

Tesco had the lowest amount of UK-origin lamb across all supermarkets surveyed, at 50% of lamb products. It was also the only retailer to reduce the amount UK-origin lamb on its shelves over the year.

The National Farmers’ Union has called on Tesco to publish its sourcing policy.

“With Brexit looming, British lamb producers now more than ever need retailers to be clear on their sourcing commitments. Tesco has seemed to shy away from making clear to suppliers and customers what its sourcing policy is with lamb,” said the NFU livestock board chairman, Charles Sercombe.

Sercombe said that farmers need clear sourcing commitments from retailers operating in the UK market, to be able to invest in their businesses: “Ambiguous sourcing only reduces farmer confidence to invest.”