The Epic Century-Long English Battle to Rid Itself of American Squirrels http://www.atlasobscura.com/articles/the-epic-centurylong-eng...
"North American grey squirrels first entered Britain as pets for the upper classes in the Victorian era, but it wasn’t until 1876 that they escaped their cages. The story goes that Thomas Unett Brocklehurst, master of Henbury Hall in Cheshire and world traveler, brought a pair of grey squirrels to this tiny island because he thought they’d look nice gamboling around on his estate. That’s the story, but the historic record isn’t clear on whether Brocklehurst really did bring the squirrels—the current owners of Henbury Hall have no record of anything pertaining to squirrels and the local historical society doesn’t either. If Brocklehurst was indeed the man, he was also something of a trendsetter. Several years after Brocklehurst, the 11th Duke of Bedford, Herbrand Russell, reportedly brought 10 pairs of the fecund little animals from New Jersey and released them onto his estate, Woburn Abbey in Bedfordshire. Russell, ironically the president of the Zoological Society of London and a keen supporter of animal conservation, was instrumental in distributing grey squirrels around the country: He set them loose in Regents Park and Kew Gardens in London and gifted them to squirrel-less friends. The population of grey squirrels, sturdy of body, chattering and robust, steadily rose." ‎- JustDuckie