In June of this year, a taxi was travelling down the secluded Napsbury Lane in St Albans, Herts, when the driver noticed an animal at the side of the road. Stopping to have a look, his dashcam captured footage of what he believed to be the mysterious creature that the locals have branded “the big cat of St Albans”, an elusive puma-like creature that has been supposedly seen on multiple occasions over the years. Sceptics might be inclined to say that it’s just a regular cat, but for many people, this is another piece of evidence in one of Britain’s longest-running conspiracy theories: that there are undocumented big cats stalking the wilds of the UK.

Reports of wild beasts roaming the wilderness have been a part of British folklore for centuries, but it was approximately 40 years ago that the big cat theory began in earnest. In 1976, the introduction of the Dangerous Wild Animals Act had made it mandatory to obtain a licence for keeping animals such as exotic big cats. It is therefore probably not a coincidence that the following few years saw a large upsurge in people reporting seeing big cats out in the wild, as unscrupulous owners who could not be bothered meeting the requirements for a licence simply set their animals loose. It was also around this time that the first stories of the Beast of Exmoor, which fits the description of a leopard, began circulating, while accounts of the Beast of Bodmin Moor originate in 1978.

Also in 1978, a jet-black cat now known as the “Fen Tiger”, was reported in Cambridgeshire. Police investigated but found nothing. Despite this, the Fen Tiger has been apparently seen on numerous occasions since then. In 1994 a man out walking with a video camera (a rare occurrence back then) captured grainy footage of a large black animal in the distance, apparently bounding away as soon as it noticed him. Unfortunately, the footage is too out of focus to tell what the animal is.

Then, two years later, the big cat conspiracy got its first piece of evidence. In 1980, Scottish farmer Ted Noble was becoming increasingly perturbed by livestock deaths caused by a wild animal. He decided to lay down a cage trap to capture the creature responsible, which he presumed was a fox or perhaps a rogue dog. Little did Ted expect that his innocuous act would become immortalised in the annals of cryptozoology. When he went to check the trap the next day, he found himself facing an animal that could not possibly be there. One can imagine him rubbing his eyes and blinking widely, dumbfounded. He could be forgiven for being slightly bewildered, as pumas aren’t animals Scottish farmers usually have to deal with.

The puma was taken to the Highland Wildlife Park, where she was named Felicity and became a star attraction until she died five years later. Felicity remains notable for being one of the few confirmed cases of a non-indigenous big cat found in the wild in Britain, whose origin remains unknown. The most likely scenario put forward is she was deliberately released by somebody who had bought a cute puma kitten and was not able to handle the adult she grew into to. Vets noted that she seemed tame, allowing people to touch her and eating food offered to her by hand. However, to this day it is unclear how the puma got into the wild, or how long she had been there.

In 1984, a gamekeeper in the village of Kellas, Scotland accidentally snared a cat in a trap. He thought the cat was rather strange in appearance and took it to somebody who could examine it. The animal was found to be a crossbreed between a domestic cat and a wildcat. It was not a fugitive pet but a new introgressive hybrid, a proper wild animal. The Kellas cat, as it was named, had been thought an urban legend for years prior to this. This further fuelled speculation about what exactly was lurking out there.

In 1989, a cat was found dead at the side of the road in Shropshire, likely hit by a car. The cat was unusually large, with more pronounced canines, distinctive ears and a narrower face than a regular cat. The body was examined and identified as a jungle cat, an animal native to the Middle East and South Asia. As with Felicity the puma, it is unknown where the cat came from or how long it had lived in the wild. As it was killed, there is no way of knowing if it was tame.

In 2001, a lynx was captured in North London. This came after ten years of supposed sightings of the “Beast of Cricklewood”, an elusive big cat seen around south Hertfordshire and the fringes of north London. Indeed, there had been so many reports over the years that police initially dismissed the call as a hoax, before realising it was genuine. The lynx was taken to the big cat enclosure at London Zoo where she was given the name Lara and treated for a broken paw and malnutrition. Like Felicity, it was never established where she came from.

In 2016, another lynx escaped from Dartmoor Zoological Park and evaded capture for three weeks, even in the face of a massive manhunt involving a police helicopter and a drone. Despite having lived in captivity its entire life, its natural instinct had kicked in and the lynx had managed to feed itself and find places to hide, going undetected for nearly a month despite being the subject of a police chase that would make O.J. Simpson feel like he got off lightly. This demonstrates how, once in the wild, these animals can adapt quickly. If nobody is looking for them, it’s possible they could survive for years. This undercuts the assumption made by sceptics that escaped big cats would naturally die off, or be found immediately if they were released into the wild.

The sceptic will of course say that these sightings are probably a misidentified dog, or a regular cat that through a scale distortion looks deceptively big in the distance, or perhaps a deliberate hoax, and that a handful of confirmed cases of wild exotic cats in forty years does not constitute a trend. It does seem a little convenient that every supposed photo of the cats is blurry, usually with the animal in the distance, running off into some bushes. However, the sheer number of sightings is hard to ignore. There are at least 15 separate legendary big cats said to be stalking the untamed regions of the UK, including the alliteratively named Dartmoor Devil, Creature of Cornwall, and the Hull Hell Cat.

These claims are not always from kooks and conspiracy theory oddballs – many ordinary and otherwise pragmatic people have claimed to see things. Dr Gary Mantle, head of the Wiltshire Wildlife Trust, is one academic who has expressed the belief that the evidence is enough to suggest there must be something hidden in the wilderness, even if we are unsure of exactly what it is. Scientists have been presented with hairs and teeth that definitely come from big cats, although they could have been dropped by hoaxers. This has not deterred some qualified professionals, such as Dr Karl Shuker, for adamantly believing that the big cats are real.

While most believers think the cats are descendants of captive animals released into the wild, a more fringe theory posits that they are remnants of indigenous Ice Age fauna that have dodged identification for centuries. If that sounds immediately ridiculous, it is worth considering that palaeontological evidence has shown conclusively that big cats such as lynxes did inhabit the British Isles at the end of the Ice Age, stranded when the ice melted and formed the English Channel, and continued to survive until supposedly being made locally extinct a few hundred years ago. But what if they didn’t go extinct? The list of Lazarus taxon – animals that have been presumed extinct, then found to still exist – is quite long. The coelacanth, a large fish, was thought to have died out somewhere between 66 and 145 million years ago, only for a live specimen to be caught in 1938. This may be an extreme example, but many animals have been rediscovered after being served with premature obituaries.

The Banggai crow was believed extinct since 1884 until a small colony was spotted on an Indonesian island in 2008, and even then it was not recognised as being extant by the ornithological community until the following year. The Australian night parrot was not sighted at all between 1912 and 1979, and there have only been five confirmed sightings since 2005. The Gray’s monitor lizard, a large reptile that reaches 180 cm in length and weighs around 9 kg at maturity (not easy to miss), was first described in 1845 and then not seen again for 130 years. The red-crested tree rat was thought to be extinct until volunteers at the El Dorado Nature Reserve in Colombia found one by chance in 2011. Prior to that, the last recorded sighting was in 1898.

The most apt comparison to make is arguably the thylacine, also known as the Tasmanian tiger. Once thriving on the Australian mainland, they were rendered near extinction by natural events about 2000 years ago, left only on the small island after which it would be named. When the settlers first arrived, stories of a strange animal mauling sheep were initially dismissed as tall tales, before it was proven that the carnivorous marsupial was real. Unfortunately, by the 1930s, the animals had been (theoretically) driven to complete extinction by hunting and habitat destruction. Even so, there are still numerous reports of sightings every year. Just this week, footage captured on a static camera shows a creature bounding past in the distance, which even experts have admitted could be one of the long lost creatures. In March, scientists from James Cook University felt the claims of a thylacine sighted in Queensland was plausible enough to carry out a search, although they found nothing.

Of course, these examples don’t entirely work, because it is a lot more plausible that an animal could hide out in the expanses of the Australian bush, or the dense rainforest of South America. The British countryside does not offer enough shelter to realistically hide dozens of large carnivorous felines without somebody noticing. So, if the British big cats are real, then why haven’t we found them? Other than a handful of examples that could be explained away as escaped pets, there is no confirmed evidence; not a living specimen, not a body, not even so much as reliable footprints or dung. How could a colony of large cats be so totally elusive? The answer to this, according to the believers, is that the government is suppressing their existence in order to conserve them. It is believed that if their existence is established, they will go the way of the Tasmanian tiger, hunted to extinction by trophy seekers and people scared about the thought of dangerous animals living in the wild. This is a nice theory but in order to believe that you would have to think that the same government that has authorised fracking and several badger culls would be environmentally conscious enough to go to great lengths to hide all traces of pumas and panthers running around the country for their own protection.

So, is it safe to assume that the British big cats are a tall tale? The answer to that is probably “yes”. While there have been a few cases of big cats running wild, they are almost always confirmed to be escaped from captivity and are recaptured, albeit sometimes only after a few weeks. With the lack of evidence being overwhelming, it seems reasonable to say that other sightings can be explained away as misidentification. Nevertheless, the legend of the British big cats doesn’t show signs of fading any time soon.