Jim Al-Khalili talks to this year's winner of the L'Oreal -UNESCO Woman in Science award, Frances Ashcroft.

After decades spent studying the link between blood sugar and insulin, she talks about the absolute thrill of discovery as well as the long lean years "in a cloud of not knowing". It's very rare indeed for a scientist to see any medical benefit from their research but Frances Ashcroft has been lucky. Her scientific understanding of a key biochemical mechanism in our pancreatic cells has helped transform the lives of hundreds of children who are born with diabetes, enabling them to come off insulin injections and instead take a daily pill.

Producer: Anna Buckley

And yet, thirty years on, it's still not clear precisely what goes wrong with the mechanism in the much more common Type II diabetes, now affecting hundreds of millions.