Subjects in the intervention group will have proven competencies both in the use of the study insulin pump and the study continuous glucose monitoring (CGM) device, and will receive appropriate training in the safe use of closed-loop insulin delivery system and low glucose feature. All subjects will have regular contact with the study team during the home study phase including 24/7 telephone support. The primary outcome is between group differences in HbA1c levels at 12 months post study arm initiation. Secondary outcomes are the time spent in the glucose target (3.9 to 10.0mmol/l; 70 to 180mg/dl), time spent with glucose levels above and below target, as recorded by CGM, and other CGM-based metrics. Safety evaluation comprises assessment of the frequency of severe hypoglycaemic episodes and diabetic ketoacidosis (DKA).