The sustainability of the dairy supply chain is a widely debated topic in the industry. The purpose of this paper is to explore farmer behaviour in response to diminishing returns and investigates the possible long-term implications of low returns, identified by farming families. The paper argues that, sustained declines in margins, coupled with other structural changes in the industry, will eventually lead to an exodus of small family farms. A qualitative methodology ensures in-depth data were collected over a five year period. The results indicate that farmers and their families are concerned over the reduced margins for their produce, with many smaller farms forced to subsidies the business with alternative sources of income. Farmers also raise concerns over the sustainability of the dairy supply chain and how future English milk supplies will meet the demand.