To reduce levels of mastitis on British dairy farms, a mastitis control programme has been developed, tested in a clinical trial, and is being implemented on a nationwide scale. The scheme, the DairyCo Mastitis Control Plan, is discussed here on the basis of describing some of the challenges encountered; we describe reasons for starting a new scheme, the major challenges faced, and how the scheme is working. In the first 234 years of the scheme, about 250 vets/consultants have been trained, over 10% of British dairy cows have received the full plan, and we estimate about a further 10% have received a partial plan. Initial analysis suggests that, on average, a reduction of around 10% per annum is being achieved in clinical mastitis and somatic cell counts in fully participating farms. This article is based on a recent paper "National Mastitis Control Schemes: Experiences from Implementation of a Nationwide Scheme in Great Britain" presented at the "Udder Health and Communication" conference, Utrecht 2011.