Diabetes care is often a trade off between tighter glucose control on the one hand and hypoglycaemia (blood glucose <4.0mmol/l) on the other. Whilst clinicians often appear to concentrate on the former, hypoglycaemia is the one aspect of diabetes care that concerns patients. Hypoglycaemia occurs more commonly than is usually thought, 10-30% of patients with Type 1 diabetes having a severe episode each year. In Type 2 diabetes, the risk of hypoglycaemia rises depending on the duration of diabetes and the increasing use of insulin. Indeed, after 5 years of insulin treatment, the risk of hypoglycaemia is equal to patients with type 1 diabetes with 5 years of insulin treatment.