Last week I went to a scarily heavyweight dinner party at the Foreign Office (guests included a secretary of state and the prime minister’s wife), and guess what we ended up talking about? Jedward. Given the venue, you might assume Jedward is the name of some sinister multinational corporation or remote Afghan war zone. Er, wrong. They’re mad-eyed Irish twins called Jonathan and Edward Grimes, 18, who are the talking point of this year’s run of The X Factor.

It was final proof, if it were needed, that the Saturday night singing contest is less a television show than a national addiction. It’s like football or DIY — there’s no part of society that it doesn’t reach. Last Sunday, 16m tuned in to see who got booted off, more people than watched any of the previous series finals. Intriguingly, while class division appears to be on the up and social mobility has lurched to a standstill, The X Factor unites taste across the board. Even the prime minister is a noted fan, sending little missives to contestants he feels have demonstrated the sort of grit and determination that made Britain great (through the medium of karaoke, obviously).

Right at the centre of the circus is Louis Walsh, the 57-year-old talent manager turned TV personality. He’s been a judge and mentor on the show since it started five years ago, and this year is looking after Jedward. So my first question is the one everyone from the sink estates to the corridors of power wants to ask: can the twins win?

He laughs (even this sounds Irish), and concedes: “If I’m absolutely honest, I don’t think they can. If they get into the bottom two then Simon, Cheryl and Dannii will vote them out.” Naturally, he’s referring to fellow judges Simon Cowell, Cheryl Cole and Dannii Minogue, who have rather taken against poor Jedward.

In fairness, the bequiffed duo aren’t great shakes on the singing front, even though their rendition of Britney Spears’s Oops! ... I Did it Again effortlessly seared itself onto the national psyche (the matching red latex suits probably helped).

“People are obsessed,” he chuckles. “It’s out of control. Peaches [Geldof] was telling me the other day that she wants to marry Edward.”

Walsh is back home in Dublin, so he’s on extra-good form. It’s his favourite place (he’s treated like a god here) and he flies back every week between shows. He’s gossipy and naughtily rude, but much more warm-hearted than you might imagine and extremely un-smug, having seen both sides of life. Born in the rural west of Ireland with little money and fewer prospects, he tipped up in Dublin in his late teens with no contacts and a ton of ambition.

“I just wanted to get out of that place,” he says. “Small village, small farm. I hated school. I wasn’t academic at all. Every Irish Catholic mother with nine children thinks one of them should be a priest and I was the eldest so it might have been me.” And why wasn’t it? “I couldn’t see myself in the outfit,” he says, with a twinkle.

“I just loved pop music so I came to Dublin after school and got a job in an office where they managed pub bands.” He started at the bottom, making tea and dishing out flyers and worked with several acts in the 1980s before hitting it big with Boyzone. “It was a bit like Jedward: it shouldn’t have worked, but it did. They’re living proof that anyone can make it if they stick together.”

He picked for the band a young Stephen Gately, whose death last month at 33 devastated Walsh. “I was in my car after The X Factor and I was getting all these texts about the show and in the middle of it was this one from a journalist going, ‘Is Stephen dead?’ Then I saw a missed call from Michael Graham, from Boyzone, and I called him and he told me. It didn’t sink in. I came back to my hotel in Mayfair and sat watching it on Sky News. It was like watching a soap I was somehow involved in.”

Walsh says he found it particularly tragic as Gately had relaxed in the past few years, unlike his younger days when he’d struggled with his sexuality. “He used to dread the papers on a Saturday night,” he says. “He used to ring me and say, ‘If they do anything, I don’t know what I’m going to do.’ He was almost suicidal about it. I used to always get him pictured with different girls. I remember putting him with Mandy Smith and Baby Spice, all these people pretending they were going out with him,” he says, with a hollow laugh.

When did he tell you he was gay? “Well I didn’t know he was gay from the audition,” he says. “If I’d known from the start, I probably wouldn’t have picked him.”

He throws his head back, keen to move on to less serious topics. Who’s got the biggest dressing room on The X Factor then, I ask? “Oh Simon, of course. He’s moved up this year but I’ve got his old one so I’m quite happy. I get ready in about 10 minutes. Those girls take hours — and by girls I mean those three girls,” he laughs. “The girl upstairs, Cowell, he’s doing that hair himself.”

Do you all get on? “Simon and me are very close. I didn’t know Dannii before X Factor. I have to say she’s looking better now than she did then,” he says, winking. “But she’s very professional and works very hard. Tough as nails, in fact. Well, she’s been in the business since she was seven, living in the shadow of her sister Kylie.”

And Cheryl? “I think she’s the new Kylie. She’s very grounded, very real. She’s got a very soft heart.”

And are she and Dannii at each other’s throats like everyone assumes? “Well . . .” he says, trailing off with a nervous laugh. “Listen, I wouldn’t say they’re the best of friends.”

But surely you all went to Simon’s lavish birthday do last month? “Oh yes, so fun,” he says. “It was over the top — just like him.”

It’s not hard to see why Cowell likes having Walsh around. At least he’d make you giggle during hour seven of a tedious day of auditioning no-hopers. “We crack each other up, that’s why it works,” he says. “I don’t like normal people and Simon’s the same. We hate when normal people come in to sing. We love them slightly bonkers.”

Like Jedward? “Exactly!” he cries. “What would we do without Jedward?”

The great and the good might wonder the same.

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