The results are revealed of a six-year medical trial into a new treatment for Parkinson's. Can it give hope to ten million Parkinson's sufferers worldwide?

In this moving first episode, cameras follow Professor Gill performing surgery on all the volunteers to implant the device he has designed that enables delivery of GDNF to a deep part of the brain. The device comprises four catheters placed in the putamen (a part of the brain key in Parkinson's) that link to a port embedded in the side of the skull through which GDNF can be infused monthly.