The provision of telephone advice to members of the general public from staff based in accident and emergency departments is common practice. However, it is largely conducted on an ad hoc basis without the use of formal guidelines or decision support. The evidence base from which to derive guidelines for the telephone assessment and advice of many common conditions is lacking. This study, using the Delphi technique, was undertaken to develop a number of benchmarks for use as objective measures against which the comprehensiveness of telephone assessments could be tested. Consensus views on the essential and desirable items to be considered for each of 10 presenting complaints was achieved. It is argued that establishing consensus views on clinical topics provides an effective means of developing an evidence base where other sources of evidence are lacking.