In 1985, British scientists made what would turn out to be one of the most important environmental discoveries of the 20th century - finding a hole in the earth’s ozone layer.

The British Antarctic Survey, based in Cambridge, had been monitoring ozone levels for more than 30 years using the Dobson Ozone Spectrophotometer.

But it was only when they compared previously uncharted figures from the 1980s with the previous decade that they made the shocking finding, as Jonathan Shanklin, the man who compiled the data, told Jane Wilkinson.

(Photo: Ozone hole in September 2006. Credit: Universal History Archive/Universal Images Group via Getty Images)