The incidence of diabetes is increasing globally, including within Europe. There is an estimated 20million diabetic patients in Europe, which is likely to increase, thereby adding to societal demands on European health services. Diabetic patients are more likely to have surgical interventions than the general population. There are plausible pathophysiology and clinical mechanisms that diabetics are at increased risk of postoperative complications. When postoperative complications occur in the general population, they increase mortality or increase risk of major adverse cardiovascular events (Myocardial Infarction, Cerebrovascular Accident, Pulmonary embolism) at 30-days and up to one year later. In addition, diabetes is an independent risk factor for surgical site infections. There is variation in practice guidelines in different countries in the perioperative management of diabetic patients undergoing major surgery, but this has not been documented on a large scale. Given the multiplicity of guidelines and differing recommendations, it is unsurprising that variability of 'real-world' clinical practice with regard to perioperative management of oral antihyperglycemic medications and insulin therapy has been noted in audits such as the National Confidential Enquiry into Patient Outcome and Death (NCEPOD). Further, although it is recognised that diabetic patients are at increased risk of postoperative complications, this has not been recently evaluated, especially in light of ongoing developments in perioperative care, such as Enhanced Recovery Programmes. While a quality improvement intervention study has shown that maintaining tight preoperative glycaemic control improves postoperative glycaemic control, it is not known if this reduces postoperative morbidity overall. Further, whether certain anaesthetic techniques may be associated with better or worse outcomes after major non-cardiac surgery is unknown.