Alien invaders

There is an alien invasion and it is costing us billions. Mary discovers the weird, wonderful and worrying world of invasive species and what we need to do to improve biosecurity. For more on the invasive species inquiry follow this link: https://www.parliament.uk/business/committees/committees-a-z/commons-select/environmental-audit-committee/inquiries/parliament-2017/invasive-species-17-19/