The NHS 111 telephone advice and triage service is a vital part of the management of urgent and emergency care (UEC) services in England. Demand for NHS 111 advice has increased since its introduction in 2013, and the service is of particular importance in light of the current pandemic and resulting increased demand for emergency care. Currently, little is known about the effectiveness of NHS 111 in terms of the appropriateness of the advice given, or about the compliance of patients with that advice. Our Urgent and Emergency Care theme aimed to address this issue by analysing a large linked routine dataset of all NHS 111 calls (n = 3,631,069) and subsequent emergency department (ED) attendances made in the Yorkshire & Humber region from March 2013-March 2017.