The second hand on the gallery clock has approximately 30 ticks left to count before Channel 4 News goes on air yet where others might be paralysed by fear, the co-presenters in the Gray's Inn Road studio are still indulging in last minute banter, Krishnan Guru-Murthy casually informing Jon Snow of "the physical resemblance between you and Max Mosley".
"Aah, but I go to different brothels," joshes Snow, as the second hand ticks on. "And you don't get caught," continues Guru-Murthy, "They're all Russians in there," explains Snow dryly.
And then bang, the most heavyweight, in-depth, internationalist of British news bulletins is being broadcast to the nation and Snow is looking into the camera and giving the audience at home the rather alarming warning: "Our missiles are ready says Iran, any place any time..."
It has been an interesting week for Channel 4 News, one in which it has once again demonstrated how its flexibility and global outlook can score points off its rivals. On Monday evening, it gained exclusive access to the courtroom in Equatorial Guinea for the conviction of Simon Mann and then followed the British mercenary into jail to interview him on the prospect of his 34 year sentence. A little over an hour before Wednesday's evening bulletin begins, correspondent Sue Turton is still inside Black Beach prison with Mann, leaving deputy editor Martin Fewell to fret over the running order.
Snow, who likes to set up camp in the newsroom from 9.30am each morning despite not going on air until 7pm, agrees to break off for a moment for a chat in the cupboard-like room which is "the first office I have ever had in 33 years of working for ITN". Though he is ebullient as he reflects that "most journalists would give their eye teeth for a job like this" he cannot help but wonder whether this "job to die for" that he has had for 19 years will shortly come to an end.
"I only hope somebody finds a formula to keep Channel 4 News going because, obviously, the money will get tight," he says, as if thinking out loud. "You do look two or three years down the line and think 'Fading advertising, et cetera.' How are they going to keep the aspidistra flying? It's a very fine aspidistra, though I say it myself.
"Look at ITV, Channel 4 and even Sky. Advertising which has kept us all afloat is retreating and diverting to the web and we haven't yet seen a formula for making money out of the web." Snow admits "nobody in their right money would spend private money on Channel 4 News because it's too expensive".
He does not have the magic formula himself ("others are paid to answer that question, I just take the money"), but no one could say he doesn't pull his weight.
On this particular afternoon, he has spent more than two hours on the phone trying to persuade a key player in the attempted coup d'état in Equatorial Guinea that "it would be vastly in his interests to come on our programme". Indeed, the whole Simon Mann scoop began with Snow himself. "I made contact with somebody as long ago as the Gleneagles summit in 2005, and it has been cooking ever since then," he says nonchalantly over a cup of peppermint tea. A spare Duchamp tie lies unfurled on his desk. "A middleman said there may be a way of getting to interview Simon Mann. I didn't believe him to be honest but I followed it up and I was absolutely amazed that it led to the crown jewels. It's a strange story but it has all the ingredients of a Graham Greene novel."
A week earlier, Channel 4 News had won plaudits for an expose of Ray Lewis, the deputy to Boris Johnson, Mayor of London.
The story was also being pursued vigorously by BBC London and prompted Johnson's team to call a pre-emptive press conference aimed at softening the blow. Typically, Snow put on his bicycle clips and headed straight for City Hall. "I had to get on my bike and go down myself, get me feet dirty," he recalls. "If you turn up yourself it's very difficult for them not to take your questions because it gets embarrassing. I was there in the front row." Several witnesses dropped out of appearing on Channel 4 News that evening, though Snow interviewed the Bishop of Chelmsford ("the bishop was watered down because he was under legal threat, he was a bit of a watery bishop") and then Lewis himself, who wrapped himself in knots answering the presenter's questions ("he got into a tautological situation, one could say").
With 7pm approaching, Fewell takes the decision to hold the Mann interview (which at the time of writing is still to be broadcast) and lead on Iran, with live interviews being lined up with American investigative journalist Seymour Hersh and Iranian-born, Israeli-based analyst Meir Javedanfar. Snow knows Iran well, having covered the revolution while a reporter for ITN and having presented Channel 4 News from the country for a special in 2006. He does not recognise the axis of evil country described by some American hawks. "When you describe Esfahan as the Florence of the east they think you're completely bonkers."
His experience of Iran also helps when interviewing the country's officials, including President Mahmoud Ahmadinejad. "When you say 'I was here'...the fangs begin to recede and the horns begin to wither."
Snow showed his own fangs earlier this year, when criticising the deal struck by the British media with the Ministry of Defence to refrain from reporting Prince Harry's tour of duty in Afghanistan in return for images of the royal in action. "I was right about Harry," says Snow. "I think we are under an obligation to keep quiet if it's a matter of national security or personal security for someone in authority but the idea that we will only do it on the basis of some sordid trade ... most of those 400 editors who signed up for it regret it and I don't think we'll have another one of those. The thing turned into a farce.
"The media was awash with the most improbable photographs. You let me know the next time you find an air-traffic controller manning a machine gun nest. It was propaganda. Every paper, every television channel had exactly the same images, there was no individual journalistic endeavour at all."
At 3pm each day, Snow spends half-and-hour knocking out his "Snowmail" email giving a taster of that night's show. He even appears in a computer game devised by Channel 4 to accompany its recent "Disarming Britain" season on violent crime. "I've got an av-i-atar or whatever you call it. I don't know whether I murder anybody, I hope I don't. I'm hoping I'm a goody." Snow, 60, is something of a cult figure with younger viewers, in spite of once having inadvertently referred on air to Britain's most notorious female vocalist as "Amy Wine-glass".
Though he admits to the weakness of being more "obsessed" with some stories than others, he does not have to drag himself into work. "In terms of morale, ethos, I think the person that anchors [a bulletin] has to be seen to be active and engaged. It would be depressing for people if I came in at 4.30pm, so I come in at 9.30am and make myself a complete pain in the arse the whole day," is how he puts it.
But Channel 4 News is not just about Jon Snow. The midday bulletin, which is more business-focused than the flagship evening programme, is very much the domain of Guru-Murthy, who points out that viewers will include people who work from home and older people who are interested in financial matters.
"It's not a dumb domestic audience by any stretch of the imagination," he says. And Fewell emphasises that if Channel 4 News picks up an exclusive story it will not hesitate to break it on the noon bulletin rather than wait for 7pm.
Guru-Murthy is a top-flight news anchor in his own right and seems little challenged by his 7pm role of reading the "news belt" round-up. In rehearsal he stands with a polystyrene cup in his hand: "33-year-old man charged with the murder of French students, blah-blah-blah ..."
Today's 24-7 culture represents a challenge to a news organisation that has been limited to a couple of broadcast windows. Consequently, Jon Bernstein, the multimedia editor, is to be given extra resources to enhance Channel 4 News's online presence and is growing awareness of the site in social networking environments such as Facebook and Twitter. He identifies marked differences between the online and television audiences. Films made by the programme on corruption in Ethiopia and suffering in Somalia have attracted great attention from an international audience.
Most popular of all has been an interview by Snow with Gore Vidal, which only just made the cut as a news piece for the 7pm show but has been the biggest hit on the website for two months. "That was something that had questionable merit on the programme but plays extremely well on the web," says Bernstein. "Does that mean we should allow the web to dictate our agenda on broadcast? No, it doesn't, but there are interesting things happening out there."
The footprint is further extended by the More4 News bulletin, which follows the 7pm show on the sister channel. It's presented by the Australian former BBC correspondent Kylie Morris, who Snow once linked to in Thailand with the words "We're hoping to talk to Kylie Minogue now live from Bangkok..." Morris says her bulletin, which has a younger audience, has "a licence to wander on the edge of news slightly more than the main programme".
Back in the studio, Snow has completed his live interviews with guests in Washington and Tel Aviv and an exchange with Hazel Blears in Westminster, in which he teases the Local Government Secretary's plans to offer incentives to voters, introducing the piece with the slogan: "What do votes mean? Prizes!" The show goes into its final commercial break (in which Snow bizarrely jokes to the gallery about having a crack cocaine habit) and finishes with a piece from arts correspondent Nicholas Glass with an irascible Frank Gehry.
Another edition of the show is over, once again demonstrating Channel 4 News's qualities, defined by Jon Snow thus: "Depth, attitude, balance and not a little humour."