Over a 1-month period all patients arriving in the accident and emergency department by ambulance following a '999' call were questioned using a standard proforma. They were assessed as to whether their medical condition warranted ambulance transfer. A number of social and practical points were analyzed to see whether they would identify any group of patients who used the emergency service without medical need. Overall 289 patients were questioned. Of these 178 (62%) were considered to have medically warranted an ambulance call whereas 111 (38%) did not. A number of features which were more likely to result in an unjustified call were identified. These would suggest that basic knowledge of first aid by the public is poor and should be improved.