A small, isolated population of Glis glis also exists in south-east England. At the turn of the 20th century, the British banker and zoologist Lionel Walter Rothschild kept Glis glis in his private collection in the town of Tring in Hertfordshire; in 1902 some of the animals escaped and reproduced, establishing themselves in the wild as an invasive species. Today, the British edible dormouse population is thought to be 10,000 strong, and Glis glis have been recorded in a radius of Tring, mostly concentrated to the south and east. The area of distribution has been described as triangle between Beaconsfield, Aylesbury, and Luton, around the southeast side of the Chiltern Hills.