The now show: Inside the high-stakes, adrenaline-filled 24-hour operation at Sky News

In the age of 24-hour news there is no respite for those behind the scenes. Rhodri Marsden visits the high-adrenaline world of Sky News and meets the people who feed our insatiable appetite for information.

'I really don't need to see Camilla Parker Bowles right now," says Jon Bennett, head of studio output at Sky News, as he reclines in his chair in the gallery and does his damnedest to direct a slick, informative round-up of George Osborne's comprehensive spending review. The various options for the next video piece are displayed before him on a matrix of dozens of television screens, and it's clear that the activities of the Duchess of Cornwall are way, way down his list.

As soon as he issues the instruction for her to be banished from the matrix, she disappears, as if by digital magic. Bennett nods appreciatively, and swiftly positions presenter Martin Stanford for the next segment so he's not obliterating a multicoloured economic pie chart. "Step in," he says. "In a bit, Martin. Bit more." Meanwhile, tape is rolling, anchors are preparing, autocues are scrolling, producers are typing, and innumerable digital clocks are marking the pulse of rolling news. The news has got to keep going.

Frequently criticised and regularly satirised, the duty of the news channels is to keep broadcasting, regardless. For ever. It's a thankless task; we demand that they're available to us when huge stories break, we tune in in droves, then as soon as we've had our fill of facts we're off again, leaving them to their weather, their vox pops, sports reports and liberal use of the word "breaking".

When Aaron Sorkin's The Newsroom was first screened last year, Sorkin said that it was an attempt to take a more positive look at a group of people who are often regarded with cynicism; critics were divided as to whether Sorkin's romantic subplots helped to achieve that, but you could certainly argue that rolling news, taken for granted and yet so frequently relied upon, deserves a break. After all, that endless procession of footage, tickers, graphics and guests doesn't happen by itself. It's the result of hard graft, adrenaline, coffee, and lots of television screens. I mean, lots.

"You'll notice that we don't talk like we're in an Aaron Sorkin drama," murmurs head of news-gathering, Jonathan Levy, as we sit down for the 8am editorial meeting that establishes the main stories for the day. The discussion is brisk and straightforward, with Osborne's spending review the main focus – although you sense that set-piece analyses of £11.5bn of government spending cuts are not the reason why most of these people began a career in news.

With Mandela still ill in hospital and the whereabouts of NSA whistleblower Edward Snowden a mystery, coverage of the swinging of the chancellor's axe feels like a broadcasting obligation while more exciting, more watchable stories wait in the wings. For example, Moors murderer Ian Brady is halfway through his mental-health tribunal, and his newsworthiness is as huge as his crimes were horrific. "That story has done very well for us," says one producer – nothing to do with viewing figures, I'm later assured, merely that it's delivered lots of facts over a three-day period and made people's jobs easier. No one who works in rolling news likes to wring desperate drops of news out of a damp flannel of a story any more than we enjoy watching it happen.

The news from Johannesburg, apparently, is that a digger arrived at the graveyard that morning – "although obviously we're not going to say that on air," adds Levy. Veteran broadcaster Jeremy Thompson is already in South Africa, literally waiting for Mandela to die, but until any official announcement is made, that story is in what Levy terms "a holding pattern"; putting Thompson on air too early would effectively be misreporting the story.

So it's Osborne's spending review that'll dominate the day's output. "This doesn't fill me with joy," says executive producer John Dowden after the meeting, "but it's a big story. There's always a balance between wanting more people to watch and doing important news. Political stuff never rates very well for anybody, but if we didn't cover the spending review, people would wonder why. We're a 24-hour news operation, a moving journal of record. Ratings, reputation and credibility are all at play. So we'll put a lot of effort into trying to make the story engaging, and explaining why it's the most important thing happening today – even if people's reaction is 'Yeah, yeah, it's just politics, innit.'"

The way that Dowden and his colleagues have chosen to bring life to the story is to send reporter Sophy Ridge to Osborne's Tatton constituency, get her to hop on a train and make a stop-start journey to London while speaking to what Dowden reluctantly refers to as "real people". "I hate that phrase," he says. "Actual humans! Anyway, it's partly planned, and partly whatever turns up. She'll be talking to passengers on the train, picking up people as she goes, stopping off to speak to a university vice chancellor who's worried about losing funding, and so on."

Why this approach? "We generally try to do things as differently as we can to the way the BBC would do them," he replies. "They're our only real domestic competition, but they've got a million times more resources than we have. We have to work out what we're going to hit, and hit it hard."

There's a strange, symbiotic relationship between Sky News and BBC News. While Sky tries to plough its own furrow and make itself as distinct from the BBC as possible, I once heard a BBC employee say that some of its editors seemed "obsessed" with Sky News's output.

"We're obviously aware of what the BBC are doing," says Sky News producer Emily Purser, "but there's no culture of 'they're doing it so we should'. Quite the opposite. Rolling news has always been our business, so we're very agile and used to doing it, while you could say that the BBC are stronger at news programmes – the 6 [o'clock], 10 [o'clock], Newsnight and Today." Dowden, Purser's boss, agrees.

"Today, the BBC will probably have Matthew Amroliwala standing outside Westminster talking to a succession of politicians who'll say exactly what you expect them to say. Sophy will be on a train in Cheshire with three colleagues and a mini-broadcasting kit in a suitcase. That'll provide us with up to three hours' output during the day."

As Osborne's announcement approaches, the gallery is calm and businesslike. No histrionics, no pacing about, no wild gesticulations, no flirtatious glances across the vision mixer (at least, none that I spotted).

Anchor for the morning, Dermot Murnaghan, is placid and easygoing, in stark contrast to the tempestuous character of Will McAvoy, played in the series by Jeff Daniels. Bennett, in the director's chair, is like the unflappable conductor of a chamber orchestra, seamlessly cueing, rolling and prompting. Jude Wardman, to his left, is tasked with keeping time and making sure nothing overruns. Dowden, to his right, is continually revising and rejigging the running order.

Suddenly, news comes through that Australian prime minister Julia Gillard has been defeated by her predecessor, Kevin Rudd, in what's referred to in Australian politics as a "leadership spill". This is the perfect excuse for a particularly large, red "BREAKING" to be unleashed. Sofia Petkar, sitting to Dowden's right and in charge of the tickers and revolving triangular prisms (referred to as "Toblerones" at Sky) that sit across the bottom of the screen, alerts viewers with the words "Leadership spill". But immediately, Bennett is on her case. "What the hell does that even mean?" he asks. Petkar begins to explain. "Change it to Gillard Defeated," he says. "Things can get pretty interesting on that desk," murmurs Dowden sympathetically. "If the smallest error is made, the whole of the newsroom will let them know." A few minutes later I spot the word "appallingly" misspelled on screen. I decide not to mention it. It's a tough job, after all.

Although, it must be said, not as tough as the job of the presenter. Both Murnaghan and Charlotte Hawkins, who precedes him on early morning show, make it look ridiculously easy – but, as Emily Purser says, accusations of "autocutie" are about as far off the mark as it's possible to be. "They've got to fill," she says, "they've got people shouting in their ear, they have to interview guests off the top of their head – it's amazing what they do." Hawkins isn't surprised that people don't appreciate the demands of her job. "But there's no hiding, here," she says. "The scripts are our baseline, but when news is breaking you might have just one line on the newswires and you need the background knowledge to be able to talk about it from a wider perspective." Doing so at 6am when you've been up since 3am after four hours' sleep must provide an additional challenge. "Yeah," she says. "I can literally sleep anywhere at the drop of a hat. I had root canal surgery the other day and I dropped off in the dentist's chair."

Hawkins has Twitter up and running throughout the show, replying to tweets and forwarding others to colleagues. "We were alerted to the shooting of Oscar Pistorius's girlfriend by a tweet sent to me from South Africa," she says. "It's great to have interactivity with viewers, sourcing questions for guests and so on – but it makes things really busy, trying to keep across everything." Social media has transformed the way rolling news works. "People choose the news they want," says McAvoy's producer, MacKenzie McHale. "No, people choose the facts they want," replies McAvoy. The rumour mill has never whirred faster and louder than it does online in the 21st century, but Dowden believes that this is just another manifestation of our thirst for news. "A TV allows you to sit back and be told stuff, while the internet allows you to make your own decisions about the kind of news you want," he says. "I can see in a decade that our main competition will come from the internet – maybe from whichever newspaper group has got the hang of rolling news by that point."

The relentless hum of the newsroom is addictive, even if the jargon is slightly bewildering. "I'll just unload from the bottom," calls out Dowden, to general agreement and no quizzical glances. Errors and problems are few; a gremlin in an autocue operator's computer provides a brief moment of drama, as does the arrival of managing editor Peter Lowe, who's concerned that one of the sponsor's messages for the Sky weather forecast ("As the rain falls over Johannesburg, we'll lift your spirits") might be inappropriate in light of Mandela's failing health. "The worst thing that can happen here is when you put something on TV that shouldn't be on TV," says Purser. "Like using a take of a reporter saying 'Oh shit' instead of their actual report." One screen, positioned just in front of Purser's desk, is devoted to keeping blood pressure levels normal in such circumstances. "We keep that feed of cute animals up there just to keep everyone calm," she says. "No idea where it comes from."

It's time for Prime Minister's Questions, which means an uninterrupted 30-minute feed from the House of Commons and thus the perfect time for a fire drill. The alarm rings, and everyone dutifully files out to the car park, leaving a couple of essential staff inside who'll be crossing their fingers that an announcement about Mandela doesn't arrive in the next 10 minutes. Or maybe they'd relish the opportunity to deal with it by themselves. "Everyone here runs on adrenaline," says Purser, "everyone has a hunger for…" Stress? "Maybe. I produce the 5pm show so I spend all day preparing everything. Then if a big story breaks at 4.55pm, that's really annoying – but at the same time it makes it the best day! We're probably destroying ourselves, mentally and physically." She laughs.

Of course, Sorkin never featured a scene in The Newsroom where colleagues giggle quietly during a fire drill. It is, by dramatic necessity, about ego, sex and power. Real rolling-news channels are more centred around efficiency, precision, attention to detail, the way that logistics, technology and sharp minds create a very rich media – a media that we tend to consume unquestioningly. The newsroom, with a small 'n', would make for a terrible drama. But it makes for great news.

'The Newsroom: the Complete First Season' is available on DVD and Blu-ray from 22 July. 'The Newsroom Season 2' airs on Sky Atlantic at the end of August