Relative values: Why isn't Modern Family a bigger hit on this side of the Atlantic?

America's top sitcom is expected to win the Emmy again this year. Sarah Hughes hears from the stars.

Relative values: the main cast of characters from the new series of 'Modern Family' (Fox)

It is America's biggest comedy, watched by 13 million viewers, name-checked by presidential candidate's spouses – both Michelle Obama and Ann Romney called it their favourite show – and expected to win its third consecutive Emmy for best comedy tomorrow night. So why is Modern Family, which returns to Sky One for its fourth season on 5 October, not a bigger hit on this side of the Atlantic?

The comedy, which follows the ups and downs of a large – and largely dysfunctional – family, has performed solidly for Sky, pulling in a respectable 1.2 million viewers each episode and regularly featuring in their top 10 most-watched shows, but it's not talked about in the same way as a Friends or a Sex and the City or in the way another Sky show, the much-hyped and soon-to-air Lena Dunham comedy Girls, almost certainly will be.

So what's the problem? In America Modern Family is credited with reviving the sitcom. It's up there with the likes of Seinfeld and Friends, the sort of show that will live on in repeats long after the final episode has aired. And, like those two shows previously, the cast of Modern Family hit the headlines when they sued 20th Century Fox this summer to bring their salaries in line with their success. They won.

Indeed, Modern Family has been so great a critical and commercial hit that this season's US network schedules are clogged with pale imitations of its formula; endless sub-standard shows hoping to tap into the original's combination of tart commentary and sweet heart.

As Jesse Tyler Ferguson, who plays Mitchell, the more uptight half of the show's gay couple, puts it: "I knew I had to say 'yes' because the script was way more interesting than any of the movies I was offered. The writers were so smart and funny; it's not surprising that we now get big names [Edward Norton, Minnie Driver and Ellen Barkin have all filmed cameos] asking to appear. They know it's good material."

His co-star Ed O'Neill, who plays family patriarch Jay and made his name as the crude Al Bundy on the popular 1980s sitcom Married With Children, agrees: "Modern Family is on the same kind of path as Married With Children in that both have described as changing the family sitcom but this is a more acclaimed show and rightly so," he says. "When I was doing Married With Children I would never run into Helen Mirren in a grocery store and have her say, 'darling it's brilliant'."

Yet that level of fandom – celebrity supporters include everyone from Steven Spielberg to Oprah Winfrey – hasn't quite translated in this country. In part that's due to a change in our viewing habits. When Friends aired in the mid-Nineties it was on Channel 4, two years before Channel Five began, in a time when television was still able to generate those so-called "watercooler" moments. Everyone seemed to be watching America's most popular sitcom because there wasn't much else to watch. By contrast Modern Family airs in an era where you can digitally record or download just about any show at any time. It might lead to greater choice but it's harder for a show to make a wide impact.

While the proliferation of TV channels goes some way to explaining Modern Family's surprising predicament, it's not the only reason. On one hand it's the perfect example of family entertainment, a safe choice everyone can watch together – hence its endorsement from the Presidential Wives' Club – but on the other its subject matter, families, generates little buzz. Put differently: Modern Family is a clever, funny and beautifully acted show, but it's not sexy.

There's also the issue of over-familiarity. When the comedy aired in America it was hailed as groundbreaking for turning a witty yet warm eye on the foibles of the modern American family. When it aired in the UK people thought, 'hmmm... a couple with three kids where the dad's a bit goofy and the mum's a bit uptight… isn't that Outnumbered?'

Dismissing the show on those grounds is a huge mistake. For Modern Family's many fans, celebrity or otherwise, are right when they hail it as one of the best American sitcoms of modern times. It's not as risky as Community, as knowing as 30 Rock or as smart as Parks and Recreation, but it's tightly scripted, superbly cast and not quite as middle-of-the-road as naysayers would have you believe.

"I think we're as groundbreaking as you can be for network television," says Ferguson. "We've got Cameron and Mitchell, a gay couple raising a baby, we've got the [May to December] romance between Gloria [Sofia Vergara] and Jay [O'Neill], we've got scenes where [supposedly dull married couple] Claire and Phil get caught having sex by their children. We're trying to make it feel fresh and edgy but it is a family show so there's only so far you can go."

The show's co-creator, Steve Levitan, argues a large part of its success comes from the fact the relationships aren't sugar-coated. Characters frequently behave badly or unpleasantly to each other, their actions aren't always understandable or even right. "So often I see people take the edge off a character because they're not likeable," Levitan said at this year's Edinburgh Television Festival. "It's OK if a character is a bit of a prick… that can be what makes him interesting."

And it's because those characters are fully-rounded and three-dimensional, not simply played for laughs, that the show manages to feel fresh even entering a fourth season. Where lesser shows would be content to play endless variations on the theme of Cameron's flamboyance or Phil's goofy mistakes, Modern Family constantly reconfigures its relationships, showing you different sides of characters you thought you knew.

The most obvious example came at the end of the last season when, having spent the year preparing the audience for a second child for gay dads Cameron and Mitchell, Levitan and co-writer Christopher Lloyd pulled a neat switch by revealing that Sofia Vergara's Colombian bombshell Gloria was pregnant.

In a less clever show that moment would have seemed like a cheap trick but, because Modern Family is so character-driven, it not only seemed right, but instantly threw up all manner of interesting scenarios from how elderly father-to-be Jay would react to what would Gloria's son Manny and Jay's other children Mitchell and Claire make of it.

It's the sort of conflict that all great family sitcoms from Roseanne to The Royle Family thrive on, and one that ensures Modern Family enters its fourth season still ahead of the chasing pack.

'Modern Family' is on Sky One from Friday 5 October, 9pm