Anthony Smith reviews those battalions of plants and animals that, since the Ice Age ended, have become, sometimes surprisingly, British. Desert dwellers on the Isle of Wight, South Americans roaming the Norfolk Broads, Africans in Margate's trees - these gerbils, coypu and parakeets are just a platoon of the army of invaders that have breached the walls of our British island fortress. How and when did they come here? And why is there so often a dislike of any new and foreign creatures colonising our so-called 'natural' countryside?

(BBC Bristol)