As part of the NHS Long Term Plan, the National Health Service has committed to sequencing 500,000 whole genomes by 2023/24. During 2019, the NHS will begin to offer whole genome sequencing (WGS) as part of clinical care for: - Seriously ill children likely to have a rare genetic disorder; - People with one of 21 rare conditions where current evidence supports early adoption of WGS as a diagnostic test; and - People with specific types of cancer for which there is likely to be the greatest patient benefit from using WGS – children with cancer, sarcoma and Acute Myeloid Leukaemia. As the price of whole genome sequencing falls and the evidence improves, we envisage that it will be extended to more conditions and therefore more patients.