A Centre for Primary Care Clinical Effectiveness Group project for a primary care quality improvement system to address falling rates of routine childhood immunisations is one of four projects awarded a total of £1 million to demonstrate how the use of data at scale can improve health outcomes, supporting delivery of the London Health Data Strategy. CHIME (CHildhood immunisation system to IMprove timeliness and Equity) will provide frontline general practice teams with digital tools allowing them to identify pre-school children registered with their practice whose vaccinations are due or overdue, review each child’s vaccination record at a glance, and access information to support conversations with parents. Shared dashboards and maps will monitor regional performance, providing near real-time intelligence for public health teams and healthcare commissioners. The project will be delivered as a partnership between general practice teams, health data teams, patients, and immunisation Leads across North East, South East, and North West London, covering 443,000 (77%) of the capital’s preschool children.