The investigators aim to determine whether chronic GLP-1 receptor occupancy has any effect on exercise haemodynamics in patients with known chronic stable angina, evidence of reversible ischaemia on exercise stress testing and angiographic evidence of obstructive coronary artery disease. Each study participant will be randomised to enter either a GLP-1 treatment arm or volume-matched saline placebo arm. Those randomised to GLP-1 will have a week's run-in phase with 0.6 mg Liraglutide followed by a week's course of 1.2 mg Liraglutide. At the end of Week 2, patients in the treatment arm will have their first exercise tolerance test (ETT). They will then be up-titrated to high dose 1.8 mg Liraglutide for another week before performing a Week 3 ETT. Patients in the placebo arm will have matched volume saline injections for the first two weeks before the Week 2 ETT and then another week of saline injections before the Week 3 ETT.