An intention in 2003 to undertake a multicentre trial in the United Kingdom of compressions before and after defibrillation could not be realized because of concerns at the time in relation to informed consent. Instead, the new protocol was introduced in one ambulance service, ahead of the 2005 Guidelines, with greater emphasis on compressions. The results were monitored by analysis of electronic ECG downloads. Deficiencies in the standard of basic life support were identified but were not unique to our service. The introduction of metronomes and the provision of feedback to crews led to major improvements in performance. Our experience has implications for the emergency pre-hospital care of cardiac arrest.