There is growing interest in the development of markets for ecosystem services, with catchments a particular focus. A pioneering approach has been undertaken in early development of a market for ecosystem services in the Bristol Avon catchment in the west of England. Development of the Bristol Avon Catchment Market (BACM) was led by Wiltshire Wildlife Trust, a nature conservation and sustainable living NGO based in the county in which much of the upper catchment is situated. BACM development was funded by multiple organisations, significantly including support from government and partnership with Wessex Water (the regional water utility). Development of a two-sided market administered by a market operator, EnTrade, facilitated market entry by asset owners seeking funding for nature conservation projects as well as potential buyers of environmental credits generated by those conservation projects. Development of the BACM encountered various barriers but also comprised many novel features, including application of a market settlement algorithm fairly sharing surplus at the point of market resolution. This report outlines the development process of the BACM including the roles of key partners, the obstacles encountered, and the solutions put in place.