The move will test the market for a dairy equivalent of free-range eggs and pork and could start a war of welfare guarantees – giving farmers a way other than cost-cutting to earn a bit extra.
UK dairies already insist that suppliers meet their own standards – usually those required for the Red Tractor farm assurance stamp, although some are beginning to insist on more attention to lameness and other indicators of herd health.
But there has been criticism for some time that the standards are not enough, when the average price of milk is kept low by an international market in milk powder and cooking cheese with no welfare guarantees attached.
Marks & Spencer plans to take its welfare measurement to another level, advised by Bristol University, which has led criticism of dairy farm standards.
David Shaw of Elvington, near York, an NFU dairy farms representative, said yesterday: "Anything which offers farmers another way of earning a bit more for milk is of interest. And one way is to satisfy what the customers want."