Tonight

Alien Invaders (17x12)

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Britain is in the grips of an alien invasion, but it’s not little green men and flying saucers that we need to watch out for, but invasive plant and animal species from overseas. It costs the UK economy nearly two billion pounds a year to control invasive 'non-­native' creatures. While some some foreign species are harmless, others pose a real threat to British biodoversity.