According to a new study more than 500 species of plants have disappeared in the past 250 years - more than twice the number of birds, mammals and amphibians. Scientists at the Royal Botanic Gardens, Kew, and Stockholm University carried out a groundbreaking global analysis of all plant extinction records to come up with the figure.

Paraic Horkan Qualified Horticulturist from The National Botanic Gardens joins Ivan to discuss what this means for the natural world.