In clinic evaluation of an "artificial pancreas" for the management of type 1 diabetes, when possible hypoglycaemia causing scenarios are simulated.

In this interventional study, we will study patients with type 1 diabetes. They will be wearing a closed loop or 'artificial pancreas' system, which consists of an insulin pump with a mathematical algorithm that adjusts insulin according to real time continuous glucose monitoring from a glucose sensor. We will use the Minimed 670g insulin pump containing the algorithm, and enlite III glucose sensor. The closed loop system will be fitted by the research team (research nurse, and doctor). The insulin pump and glucose sensor is worn as usual (external hardware, with subcutaneous infusion, and glucose sensor). The observational period will be four consecutive days and three nights and will occur in-clinic, during whcih the closed loop system is used continuously. On day 1 the participants will wear the closed loop system, and learn how to use it. On day 2 we will calibrate the glucose sensor so that it over reads the glucose value by 30% On day 3, we will continue to have the glucose sensor over read by 30% and participants will be asked to exercise by cycling on a stationary ergometer at moderate intensity (50 - 60% of VO2 max) for 45 minutes. On day 4 the glucose sensor will be changed just like in normal clinical practice, and will be recalibrated to read normally. As this study is conducted in clinic, all of the study protocol will be monitored and adhered to.