Image caption Brendan O'Carroll has said Mrs Brown's Boys appeals to an audience "left behind" by other comedies

It has been called "the worst comedy ever made," but after eight years, Mrs Brown's Boys remains a huge hit with viewers.

This was evidenced once again on Tuesday night after it won a fifth comedy prize at the National Television Awards.

When the sitcom, created by and starring Brendan O'Carroll as a foul-mouthed Irish matriarch, arrived on screens in 2011, it was generally met with critical disgust.

"Jaw-droppingly past its sell-by date," wrote the Metro at the time. "Old-fashioned," said the Guardian.

Things didn't improve from there, with the Observer calling it "shameless excrescence" in 2017.

Strong words. But at the same time, the show has grown to become one of the most-watched TV sitcoms in decades.

In 2016, it was named the greatest British sitcom in a Radio Times audience poll. It has won Baftas as well as a viewer-voted National Television Award.

Its Christmas special in 2018 brought in 6.8 million viewers, making it the most-watched programme of the day.

And a film spinoff, 2014's Mrs Brown's Boys D'Movie, spent two weeks at the top of the UK and Irish box office. A stage show, Mrs Brown's Boys D'Musical, also toured last year.

How has a slapstick comedy, hinging on a middle-aged man pretending to be a troublesome 'mammy', thrived in the gulf between critics and audiences?

"I think it's because there's a certain section of the audience that feels disenfranchised by modern comedy; an audience that enjoyed the broad, double entendre comedy of On The Buses and Are You Being Served?" says Dick Fiddy, archive TV programmer at the BFI.

"I think Mrs Brown's Boys, as well as shows like Miranda, represents a style of comedy that isn't elsewhere."

O'Carroll himself has said the success of the show has been, at least in part, down to an "Are You Being Served? audience" that has felt "left behind"; forgotten as TV comedy in the UK and Ireland embraced the alternative stand-up scene in the 1980s, evolving around tricksy, post-modern styles in the 1990s and 2000s.

"Mrs Brown represents a style of TV programming that had gone out of fashion," says Fiddy. "It's not trying to be too clever. It's just trying to make you laugh. It's raison d'être is to make you laugh."

Image caption O'Carroll's real-life partner Jennifer Gibney (right) plays Cathy Brown in the show

Before it was a TV series, Mrs Brown had a life in a radio series for RTE in Ireland, then a series of books, then a film directed by Anjelica Huston, then a stage show.

Crucially, it was this that BBC producer Stephen McCrum saw at the Glasgow Pavilion. "I don't believe in God, but I nearly did that night," he told The Guardian in 2013.

"The audience was full of 200 old women laughing, alongside ushers who were about 16 or 17 and also [laughing hysterically]. It was immediately clear: there's something happening here."

This theatricality is a key part of the TV show's makeup. The liveness of the filming is woven into each episode, with clear shots of a studio audience, frequent corpsing and ad-libbing from the cast, misplaced props, knowing addresses to camera and stagey bowing.

'We're not changing the show'

It is decidedly vaudevillian, dealing in pratfalls, toilet humour and amped-up stereotypes.

This has a lot in common, notes Fiddy, with an act called Old Mother Riley; an Irish washerwoman, also played by a man, who performed in theatres and music halls from the 1930s. "She was a larger than life character who's noisy, over the top, always getting into scrapes."

It's this lineage of comedy that Mrs Brown's Boys taps into, one that survives in Christmas pantomimes, with its end-of-the-pier bawdiness, underpinned by a pervading whiff of sentimentality.

At a time of complex geopolitical struggles and 24-hour news cycles, perhaps it's no wonder that this style, visceral and uncomplicated, holds such a large audience.

Image copyright Getty Images Image caption Old Mother Riley, played by comedian Arthur Lucan, in 1938

At the press launch for 2018's Christmas episode, O'Carroll recalled how he refused a request from BBC management to alter the programme.

At the time, Danny Cohen had taken over as the controller of BBC One. Cohen was a fan of the show and keen to keep it on air, but wanted the language toned down so it could be shown in a more family-friendly timeslot.

O'Carroll recalled: "He spent the first 10 minutes telling me how lucky the BBC felt to have found me and the family, how wonderful Mrs Brown's Boys was and how he liked that there was also pathos there and hopefully a message at the end - that families fall in and fall out but at the end of the day there's always something that keeps them together."

"I said 'Danny, can we cut to the chase? You want me to stop [swearing] so you can put the show on at eight o'clock.'

"And he said: 'Exactly.' I said: 'The show is the show. Put it at eight o'clock, or put it on at half 10, put it on at half 12, the people who want to see it will find it. But the show is the show. I don't care when you put it on, we are not changing the show'."

Image caption Last year's special was the most watched programme of Christmas Day

Writing in 2017, the Observer's TV critic commented, perhaps not entirely seriously, that the popularity of Mrs Brown's Boys "should have given a huge clue to the Brexit vote".

Are there parallels to wider national schisms in the gulf between the show's (supposedly metropolitan) critics and its (supposedly "left behind") audience?

"It doesn't help that so many of our mainstream critics have the kind of class and educational backgrounds which have historically taught them that art forms such as opera or ballet or classical music are somehow more worthwhile than TV or comedy," says Megan Vaughn, a theatre criticism researcher at Royal Holloway, University of London.

"Everyone's sense of humour is different, but our sense of humour develops via our experiences and social interactions; perhaps if we gave opportunities to new and more diverse TV reviewers, we would get criticism that was less wedded to old-fashioned cultural hierarchies, and more representative of viewers' tastes."

Whether or not the critical tide will turn on Mrs Brown's Boys, its success goes to show just how persistent its breed of humour can be. Comedy evolves, but not always in the same direction.