End lines: The map - Monsters and raving loonies

The map Spring-heeled Jack, the Beast of Bodmin, the Whitby ribbon fish ... Jonathan Dyson tracks down the truth behind monster sightings in Britain

The Glasgow Gourock

Was this carcass washed up in Gourock on the banks of the Clyde evidence of giant sea serpents roaming the waters around Britain? It was spotted by a council workman, Charles Rankin, in the summer of 1942. Measuring 28ft, like the Stronsay Serpent (see right), it had a very long neck, and a relatively small, flattened head with a sharp muzzle, prominent eyebrow ridges and large pointed teeth. It also had a long rectangular tail, and two pairs of L-shaped flippers. It had no bones other than a spinal column, and its skin was smooth but covered in 6in-long bristle- like hairs similar to steel knitting needles. Rankin said it was like a huge lizard. The find, sadly, remains shrouded in mystery. At the time the Clyde was a restricted zone because of the Second World War. Not only were photographs not allowed, but the carcass itself was taken away and destroyed, fuelling the subsequent mystery and speculation. It has since been linked to similar sea monster finds in South Africa, the Gambia and Japan.

The Loch Ness Monster

Celtic and Norse folklore tells of sea-horses seen in the Scottish lochs, but the first sighting proper of the monster of Loch Ness was by Saint Columba, a 6th-century monk, who apparently came across Nessie attacking a fellow monk and calmed it down with the sign of the cross. Since then Nessie seems to have been impeccably well behaved. But does she - or he - exist? Scientists are divided. At 25 miles long and 1,000ft at its greatest depth (twice the average depth of the North Sea), Loch Ness is certainly on a monstrous scale: naturalist Sir Peter Scott has gone on record as saying that he believes there are up to 50 such creatures hiding in the loch, all related to the plesiosaurus. In recent years, similar prehistoric- looking creatures have been reported in six other lochs, and off the coast of Cornwall and north Wales.

The Beast of Gainsborough

Big cat sightings have reached epidemic proportions. Despite the claims of some (see the Beast of Bodmin, below), these are almost certainly not previously unidentified native species, but escaped or released leopards, ocelots, pumas and lynxes. Many blame the Dangerous Wild Animals Act of 1976 which brought in stringent licensing laws for the keeping of such animals as pets: knowing they couldn't meet these requirements, the animals' owners throughtfully released them, and they have been frightening housewives and inspiring newsdesks ever since. The latest suspect, January's Beast of Gainsborough, doesn't even have the virtue of alliteration essential to make a big cat story really run - although early on, locals in West Lindsey tried to claim the animal as their own, dubbing it the Lindsey Leopard. The Gainsborough sightings follow the usual pattern: the discovery of giant pawprints, savaged livestock, drivers at night swerving to avoid a massive black beast with "staring green eyes".

The Glamorgan Winged Serpent

As recently as the beginning of this century, there were sightings of dragons in Wales, most famously the so-called Glamorgan winged serpent, said to inhabit the woods around Penllyne Castle. The serpents were claimed to be spectacularly coloured, with eyes, or perhaps gemstones, in their wings. It was said, however, that they were all hunted down because they preyed on farmers' livestock. Sceptics claim these creatures were in fact cock pheasants, and that the wide-eyed locals simply didn't get out enough. Others say bumping into a dragon in Wales today would be about as likely as running across a Cabinet minister on Clapham Common and being invited round for dinner.

The Beast of Bodmin

This elusive Cornish creature first leapt into the public imagination back in 1983, with the beginning of a wave of livestock killings and regular sightings of a huge, snarling beast. In 1995 the Government announced there was definitely no beast after a six-month investigation, but said that if there was, it was probably a puma or a lynx. Only last year, however, a 20-second video was released, which appeared to show two beastly presences and formed part of a dossier of new evidence submitted to the Government. Mike Thomas, curator of Newquay Zoo, where the video was premiered, claimed at the time that this was, in fact, a native species of big cat thought to have died out 130 years ago. A similar controversy continues to rage over on Exmoor in Devon, which has its own equally cunning, beastly presence - in 1983 it outwitted a detachment of Royal Marine commandos sent to hunt it down.

The Stronsay serpent

Legends of great sea serpents living in the waters around the British Isles go back thousands of years, and sightings continue (see , left). Was it the carcass of such a monster which was washed up on the Orkney island of Stronsay on 26 September, 1808? Fisherman John Peace spotted it first. Initially he thought it was a whale, but on closer inspection it looked like no whale ever seen: 55ft long, it had a serpentine body, a 15ft-long neck with a small head, a long mane running along its back to the end of its tail and appeared to have three pairs of legs, with five or six toes on each foot. There was a rush of interest from naturalists, one of whom, Patrick Neill, even named it, Halsydrus pontoppidani, "Pontoppidian's water snake of the sea" (after Eric Pontoppidian, an 18th-century Norwegian bishop and sea serpent fanatic). Remnants of its verterbrae can still be seen in the Royal Museum of Scotland.

Spring Heeled Jack

Liverpool boasts sporadic sightings of this man-monster who terrorises women and children and leaps effortlessly from rooftop to street to his next victim's back. But Jack - or one of his kind - first surfaced in London as far back as 1837. His early victims were all young women, and his usual practice was to leap out of some shadowy lane, rip off their clothes with his claw-like hands and breathe flames into their faces. He would then depart with huge, bounding strides, leaving his stunned, dishevelled victims behind. He was said - and still is - to have large, protruding eyes, and peculiar ringing laughter. He made his first appearance in Liverpool in 1904, where he hit the headlines after being seen bounding across the city skyline. Is this really some creature from the Netherworld? Some say the original was actually a nobleman, the misogynist Marquis of Waterford, renowned for his taste in sadistic practical jokes, and that his modern-day counterpart is a succession of bored Scallies.

The Whitby Ribbon Fish

Exhibited last year at the Natural History Museum, this is perhaps the true explanation behind sightings of giant eels or sea snakes in the North Sea. The silvery-skinned Ribbon Fish is one of the world's rarest creatures, seen only a few times a century. This 12ft specimen was washed up at Whitby in North Yorkshire in 1981. Nobody knows anything about the life cycle of the fish, and only once has a live one been filmed. In Japan, their appearance is said to herald an earthquake. Perhaps it was also a ribbon fish observed in the North Sea by the German ship, the Kaiserin Augusta Victoria, in 1912. Captain Ruser described it as 20ft long and 18in thick, and said it looked like an eel. Prodigously large eels - if not quite on this scale - have been reported in Britain: in 1995 a diver lay unconscious for 11 hours after he was attacked by a 6ft conger eel in Loch Long in Scotland.

The Canvey Island Monster

As if Canvey Island wasn't enough of a nightmare, it also appears to have a race of Dr Who-like sea-monsters living in its midsts, if two carcasses washed up on its Thames shoreline are anything to go by. The first appeared on a November day in 1954. It seemed to be a marine animal, but it also had legs and feet. Standing upright it was two-and-a-half feet tall. The feet had five toes arranged in a U-shape, and it had thick, brownish skin and a pulpy head with two protruding eyes. The next discovery, also in the Fifties, was made by the Reverend Joseph Overs who had been walking along the shoreline a couple of miles from the site of the first discovery. The second body was similar to the first, but 4ft tall. It had two large eyes teeth and gills and its skin was pink and tough. It had two legs and feet with toes in the same, unusual shape. Monster-trackers have tied in the discoveries with reports from the mid-19th-century of a strange line of U-shaped foot tracks which appeared in the snow in southern England

The Avebury Black Dog

Sightings of mysterious giant black dogs have been reported all over England for hundreds of years. The stone circle at Avebury in Wiltshire was the setting for one such appearance as recently as 1990, while in 1986 a 6ft-tall black dog terrified schoolchildren in the Wirral when it ran across their path - on its hind legs. The Avebury appearance has been connected to the local legend of a phantom black dog said to appear every year on Midsummer's Day at the Stone Age site. Black dogs have regularly been associated with sites of spiritual significance, with many cases of them interrupting church services. During a Sunday morning service at Blythburgh in Suffolk in 1577, a black dog bounded up the aisle, attacked and killed three of the congregation and inflicted strange burns on another. It is not noted whether it was wearing a collar.