Hall, though, is no fan of most of his rivals. They knock him, he says, because his paper gets the scoops; they talk about "Hall's angels" and chequebook journalism, and use other jargon that doesn't square with his perception of the NoW as "standing up for the guy in the street".
In any case, he says, he tries to keep as low a profile as possible. Colleagues told him he needed his head tested for allowing The Independent in on the key day of the week, when the paper goes to press and, as it turned out, he was breaking the story of the week. Yet he accommodates me with courtesy and good humour.
Hall's day had started at 8.45am, when he arrived at the dull, modern block that houses the NoW by chauffeur-driven limo from his Wandsworth home, in south-west London. He knew it was going to be a particularly good day because, like most NoW scoops, the Archer story had already been sewn up. It had arrived three weeks previously. At the end of October, publicist Max Clifford contacted the paper, with news that a friend of Lord Archer had a story to sell.
The paper agreed on a fee - around pounds 15,000, of which pounds 5,000 went to the charity MIND. The paper obtained, as well as documentary evidence, three taped telephone conversations between Archer and Francis discussing events of 12 years ago. As NoW stories go, it was a cinch: no honey traps, no stake-outs, no months of undercover work.
Hall himself chose to confront Archer with the story at his home last Friday. He was in and out of the Archer abode in 27 minutes. It wasn't, he admits, an entirely pleasant task. "I know Archer. I think he's fine, a character and I really like him."
Hall reads through the Saturday papers, and at 10 o'clock, Lord Archer's legal team arrives. Behind closed doors, they discuss a last-minute gentlemen's agreement that the paper should "be fair" to the disgraced would-be mayor.
The lawyers are gone by 11am. By midday, people in the newsroom are discussing rumours that the Sunday Mirror has an inkling the NoW had "something on Archer".
By 12.30, Sunday Times editor John Witherow is on the phone to Hall. "The chairman should keep his mouth shut!" jokes Hall to his fellow News International executive, before adding, "we can be hard and we can be kind [with this story], and we're being kind." He appeals to Witherow: "Will you do me a favour and not pass this on to your political people?"
Hall approves a "Lords a-looting!" headline on a page 13 story on hereditary peers pinching the Chamber's goodies as they clear their offices - the alternative, "Who's Who dunnit?'', he declares too subtle - before a light lunch, which is brought into the newsroom. By 1.30 there are strong rumours that Archer is resigning his mayoral candidacy. "It's sad," mulls Hall. "But it'd drive you insane if you thought about it. The story is true and justifiable. That's the job."
I ask him how he justifies the NoW's salacious exposes. He says that in 95 per cent of cases the paper investigates, money has been exchanged, which makes the NoW's role legitimate, in that it is exposing illegal activity. Anyway, he smiles, "the NoW has been doing that for 50 years. We're naughty and fun. I think you can navel-gaze so much you forget about the readers. And there's 12 million of them."
What proportion of the paper's stories does he pay for? "100 per cent." He makes no distinction between paying a journalist, a tipster or the subject of a story. He says that he questions a person's motives when they ask for money, but if they can prove what they are claiming and there's justification for running the story, he has no qualms. In the Archer case, Francis's motives were clear, he says: Francis was appalled that Archer could be Mayor of London; also angry at being publicly humiliated by his former friend.
Hall is disturbed from his mild-mannered defence of the paper by news that GMTV is querying rumours of "a hot Archer story". Other broadcasters are calling too. Hall agrees he will speak to all after 5pm, when the first edition goes to bed. At 2.05 he receives news that Archer has indeed quit the mayoral race. "Now look what you've done," quips an executive. The splash is rapidly changed from "Archer's false alibi" to "Archer quits as News of the World exposes false alibi".
When Archer's statement, released through the Press Association wires, comes through, Hall looks peeved. The statement ends by saying that Lord Archer doesn't want to put his family through "six months of sustained attack".
"Well, we obviously made him a liar. It's down to us," says Hall. He says he needs five minutes on his own. It's "thinking time".
At the art desk they've pulled out a picture of Archer's old rival for the Tory candidacy, Steven "five lovers" Norris. "Old slapper Norris," says one NoW hand. "There's another we can expose," adds a second. "Well at least he's open about it all," a third points out. They all laugh.
Archer spilling the beans himself makes no difference to Hall's decision to splash with the story. "What can you do? We have to go with it - just go bigger than everybody else. It's the old Sunday newspaper dilemma. If you don't go to [the story's subject] early enough you're not giving them the opportunity for a fair reply. If you go too early you give them the opportunity to put out their own statement."
A reporter is dispatched to find Andrina Colquhoun, Archer's former PA, with whom he was dining the night Francis was to cover for him. Hall had agreed with Archer not to reveal her identity, but the rules of the game have changed now.
By 2.40, Hall is agreeing to the media interviews he previously delayed: branding the story as a NoW scoop is now all-important.
Five minutes later Hall is re-scrutinising Archer's statement. The dates don't make sense to him. "He still can't get his bloody story straight after 13 years."
He turns to deputy editor Bob Bird: "We don't have to play ball with Archer now, do we?"
"Nah," says Bird. "As long as we have the statement in we're OK."
Hall approves the page 29 lead: "The legal secretary, the pizza girl and the pimp".
His merriment in the otherwise sober office is heightened when five minutes later the paper receives a tip that Gary Glitter has been stabbed in prison: "We can use that as a spread on six/seven. That's an incredible story if that's true."
Though it later transpires not to be, at this point Hall makes wings of his arms and flaps them: "Ooh, we are having an exciting day!"
At 3.30 Hall leaves a message on his home answerphone: "Hi darling, it's me. Just to let you know that Jeffrey Archer has resigned." His wife, a patent attorney, grills him non-stop on potential legals, he explains.
At 3.31 Bird tells Hall they have had their first complaint. A reader has rung to say they think "it's terrible what you're doing." The reader was told to wait and read the piece before rushing to judgment.
From then until 5pm it is non-stop media interviews. He proves a consummate broadcaster, having learnt his swift, succinct delivery standing on doorsteps in a career that started on East London locals.
In the lift back to his office from one of many live links conducted in the freezing cold outside the building, Hall shows the first sign of irritation, affronted that, yet again, he is probed over how much he paid for the story. "So long as the story is true, does it matter? We're running a commercial operation here."
A messenger comes to the newsroom with the first edition of the paper. Hall glances at it while overseeing the second edition, in which Andrina Colquhoun's identity was to be revealed.
Did he know that this would be such a big story?
"Yes," he said. "It's a dynamite mix. Jeffrey Archer. And us."