Growing up in Britain, one of my favorite folk fascinations/media obsessions was the alleged presence of big cats in the countryside. Fueled by blurry photos and living at the margins on possibility, the phenomena helped tabloids move on slow days and sometimes shaded into cryptozoology, ufology and other more delicious myths. But they're out there! Aren't they?
There have been 155 big cat sightings reported to UK police forces in the past three years, according to forces responding to FOI requests. There are likely many more never recorded. Local newspapers publish dozens of eyewitness reports every year, and have helped to firmly establish certain creatures – the Surrey Puma, the Beast of Exmoor – in local legend. Where might these cats have come from? One theory suggests they were released by their owners in the months leading up to the 1976 Dangerous Wild Animals Act. Exotic animals had been sold in Harrods; cheetahs could occasionally be seen being walked in Hyde Park. Given the choice of acquiring a costly licence or relinquishing their pets to animal sanctuaries, at least some owners chose a third option: sending cats out into the wild.
And yet they are never captured—but for a few escapees and abandonments granted no mythic fanfare, such as an elderly and arthritic puma so chill she could be petted.
UPDATE: There's a whole wikipedia article just about British big cats
The existence of a population of true big cats in Britain, especially a breeding population, is believed to be highly implausible by experts owing to lack of convincing evidence. There have been some incidents of recovered individual animals, often medium-sized species such as the Eurasian lynx but in one 1980 case a puma, which was captured alive in Scotland. These are generally believed to have been escaped or released pets that had been held illegally, possibly released after the animals became too difficult to manage. Sightings at a distance may possibly be explicable as domestic cats seen near to a viewer being misinterpreted as larger animals seen farther away. In his book Feral George Monbiot argues that humans are programmed to notice things that might be big cats because of the threat they posed in prehistoric times. A fringe theory suggests that the animals may be surviving Ice Age fauna.