Gogglebox executive producer Tania Alexander knows who makes the perfect couchbound cast member of the show, even if they don't know themselves.

"People sometimes come up to me and say: 'You should have me and my family on Gogglebox, we're hilarious.' That never works. We want people who don't know they're funny."

So when George, Linda and Pete were first cast, Linda hadn’t seen the programme. They gathered round an iPad and watched an earlier episode. “She said: ‘Why do you want us? We ain’t funny,’” says Alexander. And that was perfect.

Alexander is director of factual entertainment for Studio Lambert, the All3Media subsidiary that is helping Kite Entertainment make a 12-part Irish version of Gogglebox, the television show about people watching television, for TV3.

She is in Dublin next week to attend Mediacon, a broadcasting-led international entertainment conference, and also to give the Kite production team “a bit of a masterclass in the edit”.

Complicated

Making Gogglebox is more complicated than it might seem. TV3 originally announced that it had bought the format in 2014, but it also admitted to underestimating the production workload, saying in mid-2015 that as the casting process alone was expected to take up to six months, the show would be delayed until autumn 2016.

"In the early days I used to get really offended, when I hadn't seen my family for five weeks and would be working 95-hour weeks, when people would say: 'Oh, it's really cheap TV.' It's not easy to make at all," says Alexander, who has been doing this for the Channel 4 original since 2013.

Part of the skill in cutting the show’s unedited footage into a final edit, which typically 2½ days, is “about understanding comedy beats”, she explains – if an edit is a second too long, or too short, the laugh can be missed.

Emotions

The other editing trick is to seamlessly replicate the emotions of viewing, so that Gogglebox's viewers relate to the unscripted reactions of the cast. "Our show piggybacks off TV moments and basically enhances them. If we don't cut it well we can kill the emotion in the programme," says Alexander.

On one occasion, it took 18 hours to edit footage of the cast watching school-set documentary series Educating Yorkshire into a five-minute package.

"I'm a bit dead inside myself, but I knew this must be a bit emotional, because we had the teachers on Educating Yorkshire crying, then we had the Gogglebox guys crying as they watched it."

Ideally, Gogglebox viewers would then complete the circle by shedding a few tears too.

The show, which has several international versions, is cast “by instinct”, Alexander says. “You have got to cast people with a huge understanding of what makes your country tick, and people who viewers at home will think: ‘I recognise them.’”

Gogglebox changes from country to country. "It has to be able to meld itself to the national sense of humour. So the UK sense of humour might be very different to the American one – well, I know it is."

She is not a particular fan of the US version, which has a good following but can be “a bit snarky”, with cast members saying things like “Oh, she is so fat” about the people they see on screen.

Easy to be mean

"Don't be mean" is one of her own rules. "It is so easy to be mean. It is so easy to just say: 'This is shit.' But I don't want to show our normal people slagging off other normal people," she says. Gogglebox is not meant to be about laughing "at" anybody, including the cast who make it what it is.

The underlying warmth of the UK version was undoubtedly enhanced by the wonderful narration of comedian Caroline Aherne until her sad death from lung cancer. Aherne, as an actor and writer, understood everything there was to know about finding poignancy and comedy in the same beat.

The sense of fairness in the edit is perhaps one reason why rival broadcasters have never complained about their programmes appearing on it.

“We don’t have time to clear footage in advance and we don’t pay – we show just enough to critique and review,” says Alexander.

"There is a feeling that a show has 'arrived' if it is featured on Gogglebox," she notes.

Expect the Irish cast, which TV3 promises will be "eclectic", to give regular verdicts on The Late Late Show and other RTÉ behemoths when it starts later this month (with Deirdre O'Kane and Mrs Brown's Boys star Rory Cowan narrating). RTÉ plans to co-operate, and indeed it would be foolish not to do so.

Honour

It has become something of an honour for TV shows to be given the Gogglebox treatment. Their makers get a chance to see what ordinary viewers, as distinct from those pesky television critics, think of their work. It is as gloriously pithy and revealing as a Twitter hashtag stream, in this regard, but with the added bonus of facial expressions, family dynamics and the filters of casting and editing.

Alexander, who works with about 18 households on an ongoing basis on the Channel 4 show, plans to continue refreshing the line-up, bringing in new cast members and phasing out others. She would like to include an Irish or Scottish family and it is only the length of time that it takes to transport the rushes back to the editing suite that has prevented this so far.

For many Gogglebox fans, the show is not about television at all, but about the relationships they see on the sofa. This has had the effect of turning cast members such as Leon and June, Steph and Dom and the Moffatt family into celebrities in the UK, and means Studio Lambert cannot throw new cast members into this cauldron without a certain amount of pastoral care, including warnings to avoid knee-jerk opinions on social media.

Vitriolic reaction

"You introduce a new family and viewers hate them for a year and a half," she says wryly. The initial reaction to the Moffatts, now among the firm favourites, was "vitriolic", she recalls. "It's a bit like when there's a new family in Coronation Street or Emmerdale. It takes a while for them to bed in."

Alexander, whose CV includes the shows Seven Days, Shipwrecked, The Games, The Verdict and Undercover Boss, is currently developing a new BBC non-scripted comedy with "real people" and it will be launched in January.

Having faith in her cast has been the key to Gogglebox's surprising peak-time success. Before it aired, industry people queried how interesting it would be to watch other people watch telly.

“But I believed in the show, because I knew that people could be really very funny.”