Health Data Research UK (HDR UK) National Implementation Project: Electronic Health Records (EHR) are data generated during routine clinical interactions across healthcare settings and contain rich, longitudinal information on diagnoses, symptoms, medications, investigations and tests. EHR are increasingly being linked and used for observational and interventional studies at scale with direct benefits to human health. A primary use case for EHR is the creation of phenotype algorithms to identify disease status, onset and progression. Phenotyping however is challenging as EHR are collected for different purposes, have variable data quality and often require significant harmonization. While considerable effort goes into these algorithms, there is no consistent methodology exists for creating and evaluating them and no centralized repository for depositing and sharing them. We will landscape current national/international phenotyping approaches across stakeholders and establish an information standard for curating algorithms. We will create a national platform for dissemination of citable algorithms (incl. validations) and tools which will reduce duplication of effort and improve research reproducibility. We will explore methods for creating computable representations of algorithms for integration into actionable analytics for healthcare. Finally, we will fundamentally shift the EHR cultural landscape by a robust incentivization programme, proving guidelines on best practices, cross-disciplinary training, and ensuring alignment with other international initiatives.