Farmers who supply supermarkets say the relationship is too one sided and often unfair. Now the government has promised to set up an adjudicator to sort out arguments but farmers fear it'll be a toothless beast.
Ruth Kimber is on the National Farmers' Union council and she predicts a bit of a struggle with the supermarket lobby.
Ruth's family have farmed near Wincanton for 300 years. In the last fifty years, she says power has become concentrated in the hands of supermarkets which sell 70% of our food. She says farmers produce the raw materials but what they sometimes get back is a raw deal and she wants stiff penalties if supermarkets abuse their power.
It's tough talk. Ruth Kimber is talking of fines in the millions. And when she talks about individuals she means the Managing Directors' of supermarkets.
She's a long way from what the supermarkets want. They don't want unions or trade associations to be allowed to ask the regulator to investigate.
Cornish Yarg cheese producer Catherine Mead has never had a problem with a supermarket but she agrees the battleground will be around whether third parties will be allowed to go to the regulator.
Supermarkets say they've been a massive success story, driving down prices for us the consumer, but farmers say their enormous purchasing power is allowing them to keep too much of the profits.
Ruth Kimber points to a grower she claims had to get rid of ten acres of cauliflowers after a supermarket decided the vegetables were too big. It was a disaster that cost the producer tens of thousands of pounds.
The Kimbers sell a lot of produce in their own shop. Most farmers rely on the supermarkets. They hope the groceries adjudicator will help them plan their future with more confidence.