Loneliness is a global public health concern linked to a range of negative health outcomes (Cacioppo & Cacioppo, 2018. The Lancet. 391(10119), 426). Internationally, this has led to the development of a number of interventions, but these are rarely implemented or evaluated on a large scale. This paper is one of the first of its kind to describe elements of an evaluation of a large-scale national social prescribing scheme to reduce loneliness, deploying individual link workers to signpost people to community activities. Reporting on findings from interviews with staff (n = 25 of which 6 were repeat interviews) and volunteers (n = 9) between October 2017 and December 2018 in localities across the United Kingdom. We reflect on the complexities of the link worker role, the challenges of service delivery and the importance of community infrastructure. There was evidence that highly skilled link workers who had developed positive relationships with providers and service-users were key to the success of the intervention. As well as providing an effective liaison and signposting function, successful link workers tailored the national programme to local need to proactively address specific gaps in existing service provision. For social prescribing services to be successful and sustainable, commissioners must consider additional funding of community infrastructure.