NHS England report that the ambulance services attempt to resuscitate approximately 28 000 people from out-of-hospital cardiac arrest each year (approximately 1 per 2000 inhabitants per year).1 The rate of initial success (return of spontaneous circulation) was 25%, with less than half of those who are successfully resuscitated initially surviving to go home from hospital (survival to discharge 7%–8%, 2011–2014).1 (see figure 1). The survival rates contrast sharply with those observed in the best-performing emergency medical services systems, which have survival rates of 20%–25%.2–4 In 2013, the government's Cardiovascular Disease Outcomes Strategy for England set the ambitious, but achievable target of increasing survival from out-of-hospital cardiac arrest by 50%, leading to an additional 1000 lives saved each year