Objective: The use of donor human milk (DHM) where there is a shortfall of maternal milk can benefit both infant and maternal outcomes but DHM supply is not always assured. This study aimed to understand current DHM usage in UK neonatal units and potential future demand to inform service planning. Design/Setting: An online survey was disseminated to all UK neonatal units using SmartSurvey or by telephone between February and April 2022 after development alongside neonatal unit teams. Results: Surveys were completed by 55.4% units (108/195; 18 Level 1, 47 Level 2, 41 Level 3; cot numbers 9-56) from all thirteen Operational Delivery Networks. Only four units reported not using DHM, and another two units only if infants are transferred on DHM feeds. There was marked diversity in DHM implementation and usage. Five of six units with their own milk bank had needed to source milk from an external milk bank in the last year. Ninety units (84.9%) considered DHM was sometimes (n=35) or always (n=55) supportive of maternal breastfeeding, and rarely supportive by three (2.9%). Usage was predicted to increase by 37 units (34.9%), driven by parental preference, clinical trials, and improved evidence. Conclusions: These findings support the assumption that UK hospital DHM demand will increase after updated recommendations from the WHO and British Association of Perinatal Medicine. This data will help policymakers and milk banks to plan strategic service delivery, alongside ongoing cost-benefit analyses, donor recruitment strategies and infrastructure planning to ensure equity of assured access to DHM nationally.