1. NHS England and NHS Improvement. Letter to chief executives of all NHS trusts and foundation trusts, CCG accountable officers, GP practices and primary care networks, and providers of community health services. 17 Mar 2020. https://www.england.nhs.uk/coronavirus/wp-content/uploads/sites/52/2020/03/urgent-next-steps-on-nhs-response-to-covid-19-letter-simon-stevens.pdf.