“Take control of your sleep,” says Professor Russell Foster CBE, leading neuroscientist and this year’s opening lecturer on the festival theme of the Speed of Life. Sleeping consumes a third of our lifetimes, but Professor Foster believes our sleeping hours are still not properly appreciated. His research shows how our bodies, honed by three million years of evolution, follow a natural clock and not the man-made one in daily use. He believes that all life on the planet has developed a 24-hour timing system which humans now use to fine-tune our rhythms.

And yet Britain’s sleep problems have never been more acute: three separate surveys over the past decade indicate insomnia has increased across the population – and it’s becoming a source of public debate and private misery.

Russell Foster is Head of the Nuffield Laboratory of Ophthalmology and Senior Fellow at Brasenose College Oxford.

Producer: Fiona McLean