This is an open-label, single-centre, randomised, crossover study, involving two, 7 day (phase 1) and 21 day (phase 2) home study periods during which glucose levels will be controlled either by an automated closed-loop system or by subjects' usual insulin pump therapy combined with continuous glucose monitoring in random order. A total of up to 30 children and adolescents aged 10 to 18 years with T1D on insulin pump therapy will be recruited through diabetes clinics, to allow for 12 completed subjects available for assessment in each study phase.