Diabetes is a condition where the body doesn't produce enough properly-functioning insulin, so the level of sugar in the blood gets too high.
Nearly 90 years ago, diabetics started to use insulin injections to help control their blood sugar levels, but these injections sometimes give rather blunt control.
Swings in blood sugar levels can cause both long and short term health problems, so doctors have long tried to perfect the process of taking insulin.
Now a device known as an insulin pump may provide a solution for many patients.
Professor John Pickup of Guy's Hospital in London has been pioneering the device in Britain, and tells Health Check how the pump mimics the way someone without diabetes receives insulin from their pancreas: a slow background supply of insulin, with boosts at mealtimes.
Patients wear the pump permanently so it can deliver a constant trickle of insulin into their bloodstream, and press a button before eating to increase the dose.
Diabetic patient Andy Skinnard switched to the pump recently, having injected insulin for 20 years. He's one of just 2% of insulin-dependent diabetics using the pump in the UK.