Guinness World Records was invented by the beer company to sell in bars and to settle bar bets. In 1951, the managing director of Guinness Brewery was on a bird-hunting trip in Ireland, hunting the golden plover. After failing to shoot even one, he declared that the bird must be the fastest in Europe. His friends said no, but they had no reliable source to turn to for bird speed. So he decided the public needed an official book of records that could be used to settle bar bets.
Some time later, he hired the Norris and Ross McWhirter fact-finding agency to put together a definitive book of facts. The result was a 198-page book published in 1955 with the Guinness name on the cover that was handed out in bars as a giveaway to increase the sales of Guinness. The Guinness Book of Records was in such demand that Guinness immediately reprinted another 50,000 copies (44.7 tons) and started selling them.
In case you were wondering, according to the book, Britain's fastest game bird is the Red Grouse which, in still air, has recorded burst speeds up to 58-63 mph over very short distances. It is doubtful that the Golden Plover can exceed 55 mph, even in an emergency.