WHO would have thought it? Mrs Brown’s Boys, the BBC1 comedy made in Scotland and featuring the life and times of a Dublin mammy – and played out by a man - has been voted the nation’s Number One sitcom this millennium.

The question many will be asking however is ‘Why?’ Critics find Brendan O’Carroll’s creation to be as funny as thread veins. It’s deemed to be low-brow comedy that appeals only to the silly. Yet, it’s a Bafta winner, it’s repeated more often than The Borne Identity (shown on STV every Saturday night of the year) and Mrs Brown will run as long as O’Carroll can come up with new gags.

Do the critics have it wrong? Yes. What they fail to appreciate is the cleverness of Mrs Brown’s simplicity, the depths of the pretendy woman in the beige cardigan. Comedy writer Ben Elton explains the show’s success. "My favourite comedy of all is Dad's Army, and it's like Mrs Brown in that what you're looking at is a show where the basic joke is on humanity. It's not done in a cruel manner, it's trying to say we're all silly and desperate and not as confident as we seem."

Mrs Brown Boys is successful for other reasons. Brendan O’Carroll toured his Mrs Brown plays around the UK and Ireland for fifteen years before she made the transfer to television. O’Carroll knew what worked, and he drew from the best of those theatre plots and sub-plots and hundreds of gags and distilled them into half hour comedies. He knew this woman implicitly, (based on the writer’s own mother) and how to play her.

His character also reflects the zeitgeist, a natural complainer. Agnes Brown is Che Guevara in a dress, the voice of those who have none, but with a sympathetic heart. And O’Carroll’s woman is believable, says comedy legend Stanley Baxter. "Brendan O'Carroll makes a brilliant woman," he says. “When I first watched the series, I didn't know he was a man; he is that good. You watch closely and you'll see he has incorporated so many female traits."

Mrs Brown’s Boys also works for other reasons. Most of the cast are family or friends, which ensures a tacit acceptance that O’Carroll is always the star.

That’s why the 14,000 who voted from a shortlist of the 40 funniest shows since 2000 have a powerful voice.

Yes, The Office was more nuanced, The Inbetweeners more audacious, and Outnumbered arguably more amusing. But Mrs Brown is a traditional set-up-gag sitcom, with a light central story line and two or three sub plots, a formula that harks back to the Seventies, the days of Are You being Served and It Ain’t Half Hot, Mum. And it’s a formula, it seems, that the likes of the Peep Show and Green Wing, good as they are simply can’t contend with.

Nor do these shows have Mrs Brown lines. “Had my first cage fight last night,” she once revealed. “The fe**** budgie didn’t know what hit it.” And “Missed the gym today. That’s ten years in a row.” Classic.