As far as we know, Tyrannosaurus rex never stalked its prey through what is now the United Kingdom. Likewise, Diplodocus apparently never once set foot on British shores – despite a Diplodocus skeleton being prominently featured in the entrance hall of the UK's Natural History Museum. Neither did Triceratops, Brachiosaurus, Velociraptor or Stegosaurus.

In fact, the dinosaurs that have been unearthed in the UK are, by and large, a relatively obscure bunch. Yet Britain still holds a very special place in the history of dinosaur science.

It was there that the first fossil dinosaur fragments were studied by scientists; there that the first essentially complete dinosaur skeleton was unearthed; there that the very word "dinosaur" was born about 170 years ago; and there that the name almost died just a few decades later.

It's anyone's guess exactly where and when humans first stumbled upon the fossilised remains of ancient giant beasts. But according to Hugh Torrens of Keele University in the UK, we know exactly where the first dinosaur was discovered.

It was found in the centre of London: to be precise, at 15 Aldersgate Street, a few hundred metres north of St Paul's Cathedral.

Sometime in late 1841 or early 1842, Richard Owen – a brilliant anatomist and, by many accounts, a spectacularly unlikeable man – paid a visit to William Devonshire Saull's geological collection. There, Owen came across a rather ordinary-looking fossil: a chunk of bone from the spine of a large prehistoric animal that had been named Iguanodon a few decades earlier.

1842 is when the history of dinosaur science began

The encounter had a profound impact on Owen's thinking. Within months he would announce that Iguanodon, and two other large prehistoric animals that had also been described by scientists, were similar to one another but quite unlike anything else anyone had previously encountered.

Owen had discovered that they were something new. He called them dinosaurs.

Strictly speaking, then, 1842 is when the history of dinosaur science began. That was the year when Owen actually invented the word. But Torrens says dinosaur science had an extensive "prehistory", as the animals Owen identified as dinosaurs were already well known to geologists. Most of this dinosaur prehistory also occurred in Britain.

The story really begins in the late 17th century, before geology and palaeontology properly existed as sciences.

Earth was never inhabited by a race of giant humans

At this time, things that seem obvious to us now were far from clear. In particular, many scientists did not accept that fossils are the petrified remains of long-dead organisms.

So when Robert Plot, the first keeper of the Ashmolean Museum in Oxford, looked at fossil shells, he didn't see ancient molluscs. He saw frozen streams of urine that had crystallised in a superficially shellfish-like form.

Even so, when Plot came across a fossil that looked uncannily like a fragment from an unusually large thigh bone, he had to admit that it probably once belonged to an animal. In his 1677 Natural History of Oxford-shire, he discussed the find at great length, finally concluding that it might have come from a gigantic ancient human. After all, he argued, "Goliath for certain was nine foot nine inches high".

Plot was, of course, wrong. Earth was never inhabited by a race of giant humans.

Exactly which animal his large thigh bone belonged to must remain a mystery, because the fossil was lost long ago.

Palaeontologists now suspect that it belonged to a large predatory dinosaur

But Plot did describe how it had been "dug out of a quarry in the Parish of Cornwell": an area of Oxfordshire that was mined for limestone, which we now know dates back to the Jurassic.

From the fossil's age, and from its appearance in Plot's illustration, palaeontologists now suspect that it belonged to a large predatory dinosaur that terrorised Britain about 165 million years ago.

He got the fossil's identity wrong, but Plot was the first researcher to describe and illustrate something we would now recognise as a dinosaur fossil.

Many more early British naturalists also found and puzzled over fossils we would now identify as dinosaurs. But it was only in the early 19th century that they began edging towards an understanding of what dinosaurs really were.

Before that, an English physician called Richard Brookes earned himself a place in the prehistory of dinosaur science. In 1763 he decided to review Plot's work, and he did something that Plot hadn't done. He gave the fossil thigh bone fragment a name.

Brookes was the very first person to apply a valid name to an extinct dinosaur

With the benefit of hindsight, Brookes timed his contribution perfectly. Researchers had long been offering up names for the organisms and fossils they came across, but there was no formal naming scheme, so the results were chaotic.

The great eighteenth-century taxonomist Carl Linnaeus changed all that by introducing a binomial naming scheme, which we still use today. Names like Homo sapiens and Tyrannosaurus rex all follow his system.

To draw a firm line between the pre-Linnaean chaos and the post-Linnaean order, biologists now recognise 1758 as the official "year zero" for animal names. Any name appearing in print on or after 1 January 1758 is considered valid. That means Brookes was the very first person to apply a valid binomial name to what we would now recognise as an extinct dinosaur.

That might have been fine as far as modern scientists are concerned, if Brookes had chosen something that was suitably majestic and dignified. But he didn't. He named Plot's fossil Scrotum humanum.

Take a look at Plot's illustration and it's easy to see what Brookes was getting at, particularly if you remember that Plot thought his fossil belonged to an ancient giant man. But today's dinosaur researchers could be forgiven for wishing that Brookes hadn't put pen to paper.

The predatory Scrotum will never grace the pages of an officially endorsed book of dinosaurs

In the 1990s, two British palaeontologists actually appealed to the international committee that advises on scientific names, to have Scrotum humanum officially scratched from the record.

Happily – or not, depending on your point of view – they were successful. Since Plot's specimen is lost, we can't say with any certainty what species of dinosaur it belonged to. That means no modern palaeontologist can confidently assign a fossil to Brookes' genus or species. As a result, the predatory Scrotum will never grace the pages of an officially endorsed book of dinosaurs.

It would be another 60 years before anyone followed Brookes' lead and assigned an official name to another fossil dinosaur-in-waiting. Then two came along almost at the same time.

In 1824, William Buckland, a professor of geology at the University of Oxford, studied the fossil remains of a gigantic partial skeleton that had been unearthed in Oxfordshire. He named it Megalosaurus.

There's no doubt that Mantell made a huge contribution to science

A year later, Gideon Mantell, a doctor based in Sussex, named Iguanodon from bones and teeth. The teeth looked a lot like gigantic versions of modern iguana teeth, hence the name.

In the years that followed, Mantell would add to his growing reputation by discovering and describing more Iguanodon bones. He also found a third prehistoric behemoth, the heavily-armoured Hylaeosaurus, which he officially named in 1833.

There's no doubt that Mantell made a huge contribution to science. Some historians even suggest he was the man primarily responsible for discovering the dinosaurs, before his nemesis Owen deviously leapt in at the eleventh hour and claimed the credit for himself, simply by coming up with the name "dinosaur".

But Torrens, and some other modern writers, beg to differ.

Owen's key contribution was not dreaming up a charismatic name. It was realising something that Mantell and other geologists and anatomists had not: that Megalosaurus, Iguanodon and Hylaeosaurus shared never-before-seen anatomical features in common.

All three animals were similar to one another and different from every other animal

They weren't simply unusually large land-living reptiles. The three ancient beasts belonged to a brand new group of animals.

Perhaps the flash of inspiration came as soon as Owen saw the Iguanodon specimen in William Devonshire Saull's London collection. Perhaps it came a few days or weeks later. But at some point, Owen noticed a clear similarity between the specimen and one of the Megalosaurus bones that Buckland had described in 1824.

In both specimens, five vertebrae at the base of the spine had been fused, during life, into one solid lump. This had never been seen in another reptile. What's more, from fossil fragments Owen was reasonably sure that these five vertebrae were also fused in Hylaeosaurus.

At the bottom of page 102 of his 1842 Report on British Fossil Reptiles, he stated with confidence that all three animals were similar to one another and different from every other animal. The dinosaurs had arrived.

The year 1842 was probably something of a high-water mark for Owen's encounters with the dinosaurs.

Owen's most public legacy is the Crystal Palace dinosaurs: a set of life-size models of dinosaurs and other prehistoric beasts that can still be seen in London's Crystal Palace Park. The models, installed in the 1850s, show that Owen saw dinosaurs as stocky four-legged animals – a far cry from the swift and dynamic dinosaurs we know of today.

Even during Owen's lifetime, better and more complete fossil skeletons showed that some dinosaurs walked on two legs. This called Owen's conclusions into question, and threatened his reputation.

Not long before work began on the Crystal Palace dinosaurs, Mantell began to suspect that Iguanodon's forelimbs were "less bulky, and adapted for seizing and pulling down foliage and branches of trees".

Mantell was actually the first choice to advise on the construction of the Crystal Palace dinosaurs. Had he accepted, their appearance "might have been much more 'modern'," says Torrens.

Just as this argument was playing out, the British fossil record revealed a real treasure: the first essentially complete and fully articulated dinosaur skeleton.

Owen described the beast in 1859 and named it Scelidosaurus. But he made surprisingly little mention of the fact that it had clearly been a heavily-armoured, four-legged animal that justified some of his earlier interpretations.

Arguably, Scelidosaurus should occupy an important position in dinosaur science, says David Norman of the University of Cambridge in the UK. But it has been largely forgotten.

The idea of the dinosaurs as a single, scientifically valid group was dead

Worse was to come for Owen. As ever more dinosaur fossils came to light, palaeontologists began the job of working out the family relations within the dinosaur clan. In 1887, a few years before Owen's death, the very idea of dinosaurs was called into question.

The British palaeontologist Harry Seeley argued that dinosaurs fell into two great groups, largely defined by differences in the pelvis. The "bird-hipped" Ornithischians had pelvises like those of modern birds, and included Iguanodon and Stegosaurus. The "lizard-hipped" Saurischians, which included giant sauropods such as Diplodocus, had pelvises like modern lizards.

Seeley thought they were so different that the two groups simply couldn't have evolved from a single ancestor.

"Dinosauria has no existence as a natural group of animals," wrote Seeley. "I see no ground for associating these two orders in one group." The idea of the dinosaurs as a single, scientifically valid group was dead.

Palaeontologists accepted this for almost a century. "Many saw numerous independent origins," says Mike Benton of the University of Bristol in the UK.

These features were seen in all dinosaurs, both bird- and lizard-hipped

Not until the 1970s were palaeontologists ready again to entertain the idea that these apparently entirely unrelated groups did, after all, evolve from a single common ancestor. By then, they were realising that some dinosaurs were still around.

The carnivorous theropods, the group that includes T. rex and Buckland's Megalosaurus, live on today. We call them birds. In one of nature's greatest pranks on scientists, they evolved from lizard-hipped dinosaurs, not from bird-hipped ones.

With their warm blood and highly energetic lifestyles, birds are clearly different from "classic" reptiles, which are cold-blooded and can be sluggish. In 1974, Robert Bakker and Peter Galton argued that these features first appeared in the birds' ancestors, the prehistoric dinosaurs.

What's more, it appeared likely that these features were seen in all dinosaurs, both bird- and lizard-hipped, which all evolved from a single group living about 240 million years ago in the Triassic period. All dinosaurs shared a common ancestor after all.

Benton says a "slew of analyses in 1984 and 1985" confirmed the idea. Today dinosaurs are once more seen as a single group, as Owen first suggested, and the characters now used to define dinosaurs include an updated version of Owen's fused vertebrae observation.

If this story tells us anything, it's that the palaeontological research that took place in early 19th century Britain didn't simply set the scene for today's dinosaur studies: it continues to influence dinosaur science.

Today's palaeontologists would all recognise the importance of Owen, Mantell and the others. But the dinosaurs they described and named haven't fared as well.

The years haven't been kind to Megalosaurus.

Buckland's fossils didn't contain any obviously unique features

At various times, researchers have suggested close family relationships between Megalosaurus and several other carnivorous dinosaurs.

More recently, though, evolutionary studies have failed to pinpoint its exact position in the dinosaur family tree. Today it is a nomadic wanderer, with no close family ties to any other carnivorous dinosaur.

Worse, one analysis in 2002 concluded that Buckland's fossils didn't contain any obviously unique features that weren't seen in other, better-known dinosaurs. That suggested the name Megalosaurus ought to be abandoned entirely.

Happily, a 2008 study reversed the decision. Megalosaurus still, just about, survives as a valid dinosaur name.

The Iguanodon story couldn't be more different. Over the years, palaeontologists have enthusiastically named a wealth of Iguanodon-like animals.

Only a few Hylaeosaurus fossils have been found since Mantell's day

"We got up to about 19 names, an impressive amount of biodiversity," says Norman. Unfortunately, very few of those animals are really distinct enough to justify so many distinct names. "I have whittled it back to four," he says.

The third original dinosaur, Mantell's Hylaeosaurus has met an odd fate. It is the "Cinderella of the original triumvirate of dinosaurs named by Buckland and Mantell," says Paul Barrett at the Natural History Museum in London.

Only a few Hylaeosaurus fossils have been found since Mantell's day, and his original fossil is tricky to study. "It is embedded in really, really hard sandstone that is almost impossible to remove without damaging the bones," says Barrett. It is also far too big to fit in a CT scanner. "So presently there's not much more we can learn from it."

But you might soon hear more about Scelidosaurus, the first essentially complete dinosaur fossil ever found.

The skeleton is revealing new information

Evolutionary studies confirm that it is an armoured dinosaur, related to the famous stegosaurs and the club-tailed ankylosaurs. It turns out to be one of the most "primitive" members of the group, so it might hold secrets about the origins of the group's more iconic members.

Norman is working on the fossil that Owen described in 1859. "The skeleton is revealing new information and may well revise ideas about the early evolution of dinosaurs," he says.

British dinosaur science has a long and proud history, but it has a future too.