The Central Hall of London’s Natural History Museum is like a cathedral, except the imagery is all flora and fauna instead of deity and disciple. The combined efforts of stonework and gravitas weigh down the air and the acoustics are suitably booming. I have a friend who’s always dreamed of forming an atheist gospel choir – this would be its perfect venue.

At the pulpit presides Dr. Armand Leroi, an evolutionary worm biologist at Imperial College London, author of the award-winning popular science book Mutants and presenter of the companion TV series. His trademark bald skull is gleaming with exertion as he passionately delivers the 2004 Annual Pfizer Science Lecture entitled "The Genes That Make Us Human". The audience is keen, and there is a definite buzz to the air when a rumor sweeps the hall that some scientists peripherally involved – or at least in the know – about the recent discovery of the three-foot-tall hobbit-like humanoids dubbed Homo floresiensis are sitting near the front row. I have a nagging feeling someone is staring at the back of my head – until I realize it’s the Museum’s prized Diplodocus skeleton, towering over us all in the shadowy aisle.

My date for the evening is Jonathan Renouf, Deputy Editor of BBC Two’s Horizon, the television series dedicated to delivering science to the masses of Britain for the past forty years.

At the party before the lecture, I’d introduced Renouf to some of my scientist friends. One of them, a colleague of Leroi’s at Imperial, mentioned that he works on population genetics, mostly in yeast.

"So what’s the big story?" Renouf asks briskly, getting straight to what is, for him, the most important point.

Undaunted by this non-academic question, the scientist describes his most telegenic side project: a strategy for mustering an army of mobile "killer" genes to spread around the world instigating genocide on unwanted species such as the malarial mosquito.

"Give me a call when you’re nearly there," Renouf tells him – he sounds serious.

The scientist, in turn, wants to ask Renouf about Horizon’s recent program debunking the Atkin’s Diet. It seems he has taken exception to the part in the show when the voiceover asks, in its characteristic hushed dramatic tone, whether the diet violates the first law of thermodynamics.

"That was crap," the scientist says, not attempting to be diplomatic.

I’m a bit embarrassed by my friend’s behavior, but Renouf is good-natured and appears to enjoy the sparring. He tells me later, over dinner, that scientists sometimes do complain about Horizon’s films.

"I think there’s a tension there," he says. "There’s a core of people who regret what they see as the vulgarization of science by television. These people would rather that it were more analytical, that there was less dramatic music and language. They’d rather we reflect what they see as the sober realities of science."

He speculates that my scientist friend reacted badly to the suggestion that the Atkin’s Diet violates a fundamental law of physics because to him, it’s all a bit obvious. Of course a diet couldn’t violate that law – it’s a law: you can’t put energy into your body and then have it not tally up at the end. "That particular fact may have been a bit banal to a scientist, but I think it’s partly our job to reach for the deepest consequences of something. What we were really saying was: this is junk science. If it’s true, it contradicts one of the key bases of all the sciences."

Renouf has always viewed science as a "bulwark against irrationality". His father was a geologist, and Renouf studied mathematics, physics and geography in school. Later, he completed a degree and then a PhD in social geography. He had fully planned on becoming an academic until the day he noticed a recruitment advertisement for a new Channel 4 program – and he never looked back. After working as a journalist on Newsnight for many years, he finally moved into science TV, first on Tomorrow’s World and then making Horizon films.

Getting back to the spicing up (or "vulgarization", depending on your perspective) of science, I ask Renouf why merely presenting the science as it is, without the drama, would not be enough, provided that the story were interesting enough in its own right.

It seems it’s all about audience numbers. "If you make a film about, say, the genetics of fruit flies, then the people who will watch it will be the people who are interested in the genetics of fruit flies – and that’s a very small section of the population," he explains. "Whereas if you make a film that’s a mystery" – (here his voice becomes deeper, like a Horizon voiceover – I can’t tell whether it’s subconscious or whether he’s purposefully putting it on) – "about how the genetics of the fruit fly will reveal some fundamental secret of our own genetic nature, and it’s a story with twists and turns and people getting the answer wrong for twenty years and then suddenly someone has a breakthrough – then you draw people in because it’s a mystery…and that’s going to interest a much wider audience."

He points out that Leroi’s lecture earlier that evening had contained a great example of this technique, when he introduced two colorful Victorian scientists, Thomas Henry Huxley and Richard Owen. And it’s true: I recall being intrigued when Leroi set up the pair as bitter rivals, grappling over the evolutionary question of whether humans should be categorized back in evolutionary economy class with the apes, or instead ensconced in their own special compartment up front.

"That was great story-telling," Renouf enthuses. "It’s got two characters who you’re interested in, and it’s a battle, and you want to know who’s going to win….and there’s a twist in the end, which is that the one you think is least likeable turns out to have the most progressive views. It’s all about setting up the story and running with it." Where Leroi hadn’t scored so many points was in the scientific details: occasionally there were just too many. "He lost me with some of those graphs – I’m not sure they were all necessary for the story he was trying to tell."

Another scientist friend of mine, a French biophysicist, was recently lamenting how Horizon – once on her must-watch list – has in recent years seemed to be showing less and less actual science. Now, she told me with a shrug, she’ll watch if she’s at home, but she no longer bothers to tape the programs. Why, I ask Renouf, don’t they squeeze in more details?

"Relating complex science," Renouf counters firmly, "is the job of a lecturer, a textbook, or a schoolteacher. Not of television: on television there isn’t the space needed to devote time to such explanations to people who may never have studied the appropriate science." While one clearly needs to include enough science to make the story understandable, Renouf feels it is not Horizon’s job to put in gratuitous extra science just for the sake of it. Instead, if a program manages to interest someone, this person can then read more about the subject. "You’ve inspired them to find out more. And wasn’t that the best thing about lectures in University? It wasn’t the information you got out of it, but it was when a lecturer inspired you to go and read more yourself – or even to go and do your own research."

To Renouf, the narrative is crucial. "Science has great stories, but scientists sometimes refuse to tell them; instead they come out with comments along the lines of, ‘oh, I’m not interested in those sorts of things; I’m only interested in the science’. But it’s not true – they’re actually spending as much time worrying about other things, but they think it will besmirch their reputation if they talk about the fact that they’re, say, engaged in a bitter duel with another scientist. Whereas in the Senior Common Room –" (Renouf’s favorite shorthand for the natural habitat of the ‘real’ scientist) – "that’s what they talk about all the time. If you get someone willing to talk about these things, what you get is the human story underlying the story of the scientific discovery, and that’s a gripping story that lots of people can relate to."

Revealing the conflict behind discoveries is a favored device of the science filmmaker. Renouf offers up the clash between Albert Einstein and Niels Bohr as an example of the kind of situation that makes good television. "This was a great debate between two titanic scientists; in the end it came down to those famous quotes about god playing dice; it didn’t come down to a discussion of abstract theories, it came down to two famous scientists using metaphors which anyone can understand to try to reunite them. It was absolutely brilliant."

But could it be taken too far? I mention a recent Horizon film (What Really Killed The Dinosaurs?) in which the scientific facts about possible meteor impacts were almost overshadowed by the vitriolic backbiting between the two scientists they’d featured – humorously enhanced by a CGI clip of giant reptiles bashing heads.

"And very gratified we were that they actually said those things, because quite often scientists won’t be that frank about each other on camera!" He is visibly delighted at the memory. "It showed what science is really like. And other people say, ‘well, that’s so crude…we’d rather see the science’. But this is not just good story-telling – it’s true to the real situation."

It all seems a bit laddish to me, so I ask him if competition is the only driving force behind Horizon’s narratives.

"One of the biggest challenges for TV makers is to capture the excitement that makes scientists come into their lab at midnight to see their result – you know, that’s a human thing," he says. "It’s not the results themselves that we care about – it’s that excitement that makes great stories." He points to one of Horizon’s classics, Fermat’s Last Theorem, which is essentially a love story between a scientist and his mathematics – not a whiff of competition in sight. (Interestingly, he says that this program was a favorite amongst scientists.)

Science filmmakers can also get an audience more involved by commissioning real experimentation to illustrate or explore a controversial point – a technique Renouf personally would like to use more, if there were a bigger budget to fund scientists to help out.

"The problem is that it’s not necessarily the kind of science that a lot of scientists would want to do," he says. "It might be too trivial for them, even though the audience might be crucially interested in one of these minor points. Sometimes a simple experiment can illustrate something so much easier than the entire thing being plotted out dramatically. But it wouldn’t necessarily be an experiment that would be accepted as a peer-reviewed paper." As an example, he points to Horizon’s filmed experiment commissioned by the Royal Society a few years ago to set the record straight about homeopathy. "The Royal Society loved that film," he remarks. "They showed it for months on a continuous loop in the lobby."

Fiction can also provide inspiration and interest to a scientific topic. Future Fantastic, the first science film Renouf ever made, predicted what life would be like in the far future, as divined by real scientific expertise blended with the speculations of writers such as Jules Verne, H.G. Wells and Arthur C. Clarke. Future Fantastic also produced a program centered on Kim Stanley Robinson’s famous science fiction trilogy about man’s colonization of Mars, exploring how his vision measured up to actual scientific reality and possibility. Similarly, the cyberpunk novel Neuromancer, by William Gibson, was the inspiration for another Future Fantastic film about the human brain. "Science fiction writers like Gibson are very influential," Renouf says. "They have a lot of ideas. Gibson affected how we think about computers – you can see his ideas in The Matrix."

While we’re on the topic of fiction, I ask him what he thinks about how scientists are portrayed in novels and films.

He thinks the primordial stereotype was the mad scientist: "HG Wells, The Time Machine, the Frankenstein figure laboring away on his own with a bit of a crazy idea. That’s a staple still – even in Back To The Future, there’s this crazy scientist with a crazy idea. And it’s grounded on people like Einstein. In a way, you could say he was crazy: that’s why he had those brilliant ideas. He sat in a patent office and played mind games which none of us could play: ‘What would it be like to travel on a light beam?’ And out of that thought would come this huge theory. And he looked the part as well."

Einstein aside, the general public doesn’t seem to have a good idea of what scientists are really like, especially now, when the career has become so professionalized. I’m interested in how they are portrayed by science TV people, because the labs and scientists I see on documentaries don’t always ring true with my own experiences as a scientist – is some kind of editing taking place? I ask Renouf whether he tends to select people who are more interesting, or whether he tries to work with scientists to make them more so.

"Sometimes particular scientists are so intrinsic to the story, they absolutely have to be in the film," he says. "But sometimes they’re not going to come across well on TV. This doesn’t mean they’re boring people – the ability to appear naturally good on television is very rare. So then you’ve got a television problem: how do you make someone who is not a naturally good performer appear good? So we do work very, very hard – that can involve spending a day with them, finding out about their lives, get them to talk, try to find the one thing that makes them tick, in a way audience will relate to. And then we work that into the story."

And if they’re a lost cause? "When people aren’t intrinsically essential to the story, then you have a choice about who you can use. And then, yes, you absolutely do choose the people that you think will do well in front of the cameras. And it is a skill; some people are deliberately practiced at it – these tend to be American, not exclusively, but certainly in America they tend to know what the media is looking for in terms of quotable quotes. They are aware of the image they want to portray to the camera."

But the fear of peer reaction is an ever-present barrier. "There’s a strong feeling when you interview a lot of academics that they’re most worried about what the Senior Common Room is going to think when they see the film. If that’s the thought that’s in your head, then it’s usually the case that you will not be good on film. Because you’ll want to qualify everything you say – ‘oh, but on the other hand this, or but of course we don’t know for sure that…’. Everything you’re saying will try to be as multi-layered as possible, and that’s not what we want."

Can you edit out those qualifications? And is it even appropriate to do so?

"I don’t think it’s about us editing out qualifications necessarily – if there are genuine scientific qualifications, you can’t ignore them – but it’s about where you put them. It’s about how you manipulate the information to tell a good story – and still remain true to the facts."

For example?

"The qualifications are things that can be introduced fifteen minutes after you introduce the first statements. The point of telling a story is that you break it down a certain way; you might run with an idea for ten to fifteen minutes – someone has an idea, they think that this gene is responsible for this disease, so for years" – the hushed, dramatic tone has returned – "they struggle to prove it: they study it in mice, they study it in apes, and it all seems to add up – until somebody else comes along. Another way of saying that would be: ‘originally we thought it was this gene, but now of course we know that it’s much more complicated’. You’ve missed out all the story-telling! You’ve missed out on all the fun of it. Let’s enjoy the fact that they went down the wrong path."

I ask him whether he ever alters a scientist’s surroundings to make better TV.

"Quite often there’s pop music playing in the background – that’s got to go for technical reasons," he says. "You can’t have music you haven’t cleared for world use in the background, and it creates continuity problems during editing. So no music. Then you’re going to play with the lighting. Turn off these boring fluorescent lights and let’s get some decent light in here!"

Luridly colored lights, perhaps?

"Color gels are so nineteen-nineties!" he says, laughing. "But you will play with the lighting. Overhead lights are very flat and don’t bring out any texture, depth or drama."

And the clothing?

"You might play with the clothing. If they’re doing something with a drill, you might get them to put on goggles and a mask or whatever. I’ve never gone to the lengths of saying, ‘OK, you’ve got to wear a lab coat, and we’ll buy one for you to wear.’ Usually they’re hanging up just over there –"

"Unused?" – white coats being shunned by a fair chunk of the scientific community.

"Unused," he concedes. "But they’re in the lab; they’re there because people are somehow expected to wear them. Yes, we do manipulate the environment, but I don’t think we do serious injustice to the truth."

I am deeply curious whether these manipulations are performed for the sake of credibility or for the sake of interest. In other words, are the filmmakers trying to make the scene more colorful, or are they giving people what they like to see, or expect to see?

"I think there’s a credibility issue," he says, after some thought. "If you’ve got a top scientist doing genetics in a lab and he’s dressed in jeans and a Motorhead T-shirt…" He shakes his head. "So maybe we are portraying stereotypes." But he explains that there are more important considerations that have to take precedence. "If you’re going to deviate from what the audience expects, you have to explain it. Television is visual – a lot of the message is conveyed by pictures. And if your pictures are fighting with your words, you’ve got a real problem."

But he is always on the lookout for opportunities to make scientists into more sympathetic or interesting characters. "In general, we much prefer to find people with something different about them and try to make something of it." He gives me the hypothetical example of a scientist with rather untraditional ideas or approaches who happens to ride a motorcycle in real life – then the filmmaker would want to show his casual style, because a crucial scientific point might be intrinsically tied up with this particular scientist’s ‘maverick’ tendencies. "And we might have rock music playing in the background because that’s what they do; it’s intrinsic to their creative, scientific endeavor. That’s how they did it – they were different from everyone else."

To me, this explanation jars: the standard uniform in most labs actually is the jeans/T-shirt combination (and though it’s problematic to film labs with their CD players blasting in the background, this is usually what you find in labs). If science filmmakers classify a rare scientist as a maverick, and symbolize this with rock music and casual clothing, then the implicit message is: this is unusual, most scientists don’t look or act like this. And this is an inaccurate message, just as inaccurate as encouraging a scientist take off his beloved Motorhead T-shirt in favor of more formal clothing he’d never normally don. These portrayals will only perpetuate a myth that future viewers will again insist on seeing in order to believe. When will the cycle end? At the same time, I do understand Renouf’s problem – and can think of no easy way to solve it.

As dessert is cleared away, I ask Renouf to summarize how he sees Horizon’s role in science communication.

"We try to present ourselves as a voice of authority and clarity in a complex world. If you read Heat magazine you may think that the Atkin’s diet is a good thing because all the celebrities are doing it, but you might read somewhere else that it doesn’t work at all. So watch Horizon and find out the truth. And that’s what you can do when you’ve got a quality TV show which people trust and respect."

Even though some scientists will find it over-the-top?

"The Atkin’s Diet program has been hugely successful," he says. "If we’re asked to select one over the past few years to symbolize what Horizon is, we’ll often choose that one, because it engaged with the public, with real public concerns. We tried to put the theory to the test and we came out with a clear answer at the end."

He pauses for a moment, then adds: "We can’t do the programs without the scientists. Even if they don’t agree with us, I want them at least to see where we’re coming from, for them to understand why we’re doing what we’re doing, to see that it’s not some horrible plot to come in and corrupt their work. All these decisions we take, everything we do really, is by that desire to communicate science to as wide an audience as possible. I hate the thought of scientists seeing us as an enemy – the excitement of science is what drives us all forward."

Horizon programs can be seen on BBC 2 in Britain, and on BBC World everywhere else. Click here for a link to BBC Horizon.