There was a piece on the local news programme last night about the plight of dairy farmers in the region. Many of them are committed to the large retailers and are tied to fixed prices with them. Because the costs of feed, fertiliser and transport are all going up, many of them are in danger of going out of business. Their profit margins are low because they deal in bulk so the effects of the increase in costs will be catastrophic. If the supermarkets don't stand down and renegotiate the prices then they will lose a lot of their supply. From what I understand, there is a huge mark up between source and retail prices, so the supermarkets could easily pay more for their supply and absorb this without passing on to the consumer. It's serious apparently.