Hallam first practised medicine in the UK, where she trained to be a consultant anaesthetist. Her focus for the last 17 years however has been on global health.[5] She worked at the Royal Free Hospital.[6] In 2007 she travelled to Ethiopia as a volunteer with Health Volunteers Overseas teaching on a Masters course for nurse anaesthetists and then working in development of paediatric health services with local health providers, building capacity and conducting research on how to best manage critically ill children with pneumonia with Professor Katherine Maitland and Imperial college london.[3] She has also worked in hospitals near Aleppo and across Syria.[1]