Helen Mark goes to Down House in Kent, the home of the naturalist Charles Darwin, to find out how he used plants in his garden and the surrounding landscape to develop his theory of evolution by natural selection.

Darwin lived at Down from 1842 until his death about 40 years later. His famous theory was published in On The Origin of Species in 1859, some 20 years after his voyage on the HMS Beagle. Head Gardener Antony O'Rourke explains how Darwin went on a 'voyage of the mind' at Down, and spent much of his life devising experiments using local flora and fauna to rigorously test his theory. Darwin made forays into the surrounding chalk down landscape to observe native flowering plants like orchids and primroses. We visit the Down Bank nature reserve to hear why Kent is such a hotspot for orchids and how it provided the inspiration for the final paragraph of On The Origin of Species.

Producer: Sophie Anton