Patients with diabetes have a higher incidence of heart failure and worse outcomes than normoglycaemic subjects. Basic science research has suggested many mechanisms for this observation including endothelial dysfunction, abnormal calcium handling, fibrosis and activation of the renin-angiotensin-aldosterone system (RAAS), but clinical data are lacking. In this study the investigators will investigate the relationship between diabetes and heart failure by exploring the correlation between microvascular dysfunction and cardiac magnetic resonance (CMR) markers of left ventricular (LV) hypertrophy, cardiac dysfunction and fibrosis. The investigators also propose to see if this relationship is independent of blood pressure and markers of RAAS activity. This could have important clinical ramifications in type 2 diabetes by increasing the indications for treatment with RAAS inhibition or making a case for lower blood pressure targets.