The UK Prospective Diabetes Study (UKPDS) set out to establish whether improved glucose control could alleviate the macrovascular and microvascular complications of diabetes and to compare the relative merits of diet, oral glucose-lowering agents or insulin in achieving this objective. The study broke many of the rules of trial design, not least by constant addition of further interventions and analyses, but this flexibility would, paradoxically, prove to be one of its greatest strengths. The UKPDS taught us that glucose control must be tackled aggressively in Type 2 diabetes. It taught us that treatment must be escalated in parallel with the evolution of pancreatic B-cell failure. It also taught us that glucose control is not enough: the central objective of therapy is to reduce vascular risk by any means available. This commentary looks back along the winding road that led to these conclusions.