Last week, Brendan O’Carroll, our most famous profane old lady, was asked (not for the first time) about his attitude to the critics.

“I write for the audience, we perform for the audience, and the day I write something for a critic is the day I’ll cut my own throat,” he remarked.

We have good news. Nothing about Mrs Brown's Boys D'Movie, which premiered in Dublin last night, suggests that O'Carroll will be wielding the knife any time soon.

Every bit as crude, ramshackle and creaky as the source TV series, the film finds the titular (ooh, er!) Moore Street trader unleashing the usual malapropisms as she seeks to evade evil developers and malign Russian gangsters.

D' Movie is unlikely to elbow aside many Turkish art films when critics come to compile their end-of-year polls.

The picture is, however, certain to be a significant hit.

It is hard to overestimate the success of Mrs Brown in all her incarnations.

Conceived for RTÉ radio in the early 1990s, she has gone on to star in plays, books and, most conspicuously, the current TV series, produced by BBC Scotland.

The same pattern repeated itself in Britain. The critics sniffed. The audience howled. Astonishingly, the last two Christmas specials have beaten the likes of EastEnders and Doctor Who to become the most watched shows over the festive period.

So, what's going on? Speaking to The Irish Times for an interview to be published in tomorrow's paper, O'Carroll addressed the shift in comedy that happened during the Thatcher years. Traditional comics such as Jimmy Tarbuck and Bernard Manning were derided as a new wave of aggressive, more politically engaged performers introduced creative anarchy to the airwaves.

“Comedy became more snarky. It was more about the universities. For a long time nothing filled that void,” he said.

“I think that Mrs Brown is comedy for the audience that got left behind.”

There is a great deal in this. The more traditional situation comedies never completely vanished.

But commissioning editors (most of whom had, indeed, been to posher universities) became increasingly wary of old-school comedies shot on multiple cameras before live audiences.

Mums and grannies enjoyed The Good Life and Are You Being Served? The new generation would leave convention aside for iconoclastic shows such as The Young Ones and The Day Today.

It was inevitable that the cycle would bring us back where we started. Two of the biggest shows on British television look as if they could have been plucked, unedited, from the 1970s schedules: the very working class Mrs Brown's Boys and the very middle class Miranda.

To be fair, O’Carroll’s series is a deal filthier than shows of that era – Mrs Slocombe’s cat notwithstanding – and is more playful in its experiments with breaking down the fourth wall.

But Mrs Brown's Boys owes almost nothing to those noisy innovators of the 1980s. The audience for that older school of comedy never went away.

None of this would matter much if the show did not have a character worth savouring at its heart.

Partly based on O’Carroll’s mother, the late TD Maureen O’Carroll, Agnes Brown is less grotesque than early music-hall acts such as Old Mother Riley. She is less fantastic than the enormous Dame Edna Everage.

For all the lunacies that surround her, O’Carroll’s creation feels strangely solid, grounded and believable.

Few critics will rave about the film, but only the meanest will begrudge O’Carroll his success.