Background: Social prescribing (SP) is growing rapidly across the world as a way to tackle social determinants of health. However, whom it is reaching and how effectively it is being implemented remains unclear. Methods: This study undertook the first analyses of a large database of administrative data from over 160,000 individuals referred to SP across the UK. Data were analysed using descriptive analyses and regression modelling, including logistic regression for binary outcomes and negative binomial regression for count variables. Findings: 72-85% of referrals for SP were from medical routes (primary or secondary health care). While these referrals demonstrate equality in reaching across socio-demographic groups, individuals from more deprived areas, younger adults, men, and ethnic minority groups were reached more equitably via non-medical referral routes. Despite 90% of referrals leading to contact with a link worker, only 38% resulted in any intervention being received. A shortage of provision of community activities - especially ones relevant to mental health, practical support, and social relationships - was evident. There was also substantial heterogeneity in how SP is being implemented across UK nations. Interpretation: Non-medical referral routes could play an important role in addressing inequality in accessing social prescribing, therefore should be prioritised. Additionally, more financial and infrastructural resource and strategic planning are needed to address low intervention rates. Further investment into large-scale data platforms and staff training are needed to continue monitoring the development and distribution of social prescribing.

The authors have declared no competing interest.

This work was supported by the Prudence Trust INSPYRE grant [PT-0040], the MRC [MR/Y01068X/1], and the Nuffield Foundation Oliver Bird Fund and Versus Arthritis OBF/FR-000023818. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. We thank Access Elemental for granting us the data access.

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The research project was approved by the UCL Research Ethics Committee (23909/001).

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