Inclusion Criteria:  Patient who has a documented Type 1 diagnosis (diagnosed under age 29), or Type 2 diabetes for more than one year (with negative GAD antibody test results) and who are willing and able to give informed consent for participation in the study Male or female patient Patient aged 18 to 80 years Patients with a BMI 18-35 kg/m2.  Exclusion Criteria:  The patient may not enter the study if ANY of the following apply:  Type 1 patients diagnosed after age 29 Type 2 patients with positive GAD antibody test results Patient with other active implantable medical devices, such as pacemakers Patient who is currently participating in another clinical trial for a pharmaceutical product Patient with a history of allergy to any materials used in the prototype sensors or materials used to stabilise the devices or cabling including Rocktape, double-sided tape and prosthetic adhesive Female patient who is pregnant or lactating  Patient with any injury or infection of the wrist Patient who is unwilling or unable to attend each visit fasting from midnight (water is permitted freely) or fasting for a minimum of 3 hours (for an afternoon session) Patient who takes paracetamol or aspirin in the 24 hours preceding each visit Patient with clinically significant abnormal values in clinical chemistry, as judged by the PI Concurrent illness or a condition that may interfere with blood glucose levels (e. g. carcinoma, haematological disease, vasculitis, connective tissue disease, alcohol neuropathy) Patient who is incapable of giving informed legal consent Recent (1 month) episode of DKA, HONK or severe hypoglycaemia Patient on pramlintide (Symlin/Tripro-Amylin) Patient who attends the visit under the influence of alcohol or recreational drugs Patient with severe macrovascular disease - stroke, CVD, CKD stage IV -V Patient who fails screening for alcohol and recreational drugs use.