Objectives: The aim of this study was to derive specific clinical indications for surgery in patients with chronic critical lower limb ischaemia and to determine the extent to which practice in Scotland conformed to these indications. Design, materials and methods: Consensus on indications was achieved using a modified Delphi method in which a postal questionnaire was completed by 29 vascular surgeons on two occasions, with feedback between the rounds. Respondents indicated the appropriateness of arterial reconstruction and primary major amputation for 218 case scenarios comprising all possible combinations of clinical and angiographic findings. Results: Agreement was reached on 31 appropriate indications for major amputation and 65 for arterial reconstruction. In 10 hospitals in Scotland, 400 primary amputation and arterial reconstruction operations were reviewed retrospectively and compared with the indications. The clinical findings for 7 (4%) arterial reconstructions and 48 (24%) major amputations did not conform to the indications agreed by the Delphi method. The proportion of operations conforming to the agreed indications differed significantly by size of unit (p<0.025). Conclusions: This study shows that consensus can be reached on indications for surgery. However, in practice some operations performed do not conform with these indications. This discrepancy may be due to inappropriate practice.