Two celebrity chefs have urged the public to boycott some supermarkets over cuts to the price of milk.
In a letter to the Times, Jamie Oliver and Hugh Fearnley-Whittingstall said “cynical” retailers paying less for a litre of milk than it costs to produce were making dairy farming “unviable”.
But the British Retail Consortium says supermarkets pay well and other milk purchasers should be scrutinised.
Hundreds of farmers are to protest at cuts by processors of up to 2p a litre.
Farmers for Action (FFA) said marches would be held later in Staffordshire, Somerset, Leicestershire and Yorkshire.
Andrew Hemming, the vice chairman of the pressure group, said: “We want all dairy farmers to receive a milk price which covers their production and allows them to make a small profit for them to be able to supply the country not only for the next six months but the next 20 years.”