MRS Brown - D'Movie is set to light up our cinema screens.

But while the sitcom attracts 11m viewers on BBC1, and it's repeated more times than Mrs Brown uses colourful language in an episode, will D'Movie be a D'Isaster?

Hit sitcoms transfer as easily onto film as Agnes Brown moves from baggy cardigan to shimmering ballgown.

Look back over the years and few have made it. The Likely Lads, On The Buses and Porridge managed to pull decent audiences at the cinema.

And more recently The Inbetweeners carried on its television success.

But dozens more have failed. Steptoe and Son, Rising Damp and 'Till Death Us Do Part never hit the mark set by their sitcom counterparts.

Bless This House, Bilko and Bewitched made a case for the argument more is usually less.

So why do sitcoms find it so hard to move on to celluloid?

"The problem is context," says Rab C.Nesbitt writer Ian Pattison who helped steer Mrs Brown writer Brendan O'Carroll through the first troubled waters of his sitcom creation.

"Viewers don't like to see their heroes being relocated. They like to see them in their familiar living room or pub but what happens when the sitcoms move to film there is an hour more to fill.

"What writers tend to do is take the action abroad. But before you know it, the cosy characters who lived routine domestic lives are suddenly caught up in a diamond heist. And where a sitcom was once set in a living room, suddenly the viewers are watching Lawrence of Arabia."

It was all very for the Inbetweeners to take off to Ayia Napa (a natural journey for teenage boys) but taking Steptoe and Son out of the junkyard and off to Spain took the viewer out of their comfort zone.

The Alan Partridge movie worked to a degree but then it never followed a traditional sitcom format, instead utilising lots of exterior shots. And Partridge's world was very much inside his own head.

The same could be said for The Likely Lads.

Dad's Army however didn't do well at the box office. The change in location didn't help, nor did the added sub plots and characters. The writers, literally, looked to have lost the plot.

So will D'Movie travel as well as On The Buses? Agnes Brown has her work cut out because D'Plot reveals she is to breathe fresh air for the first time.

Mrs Brown, we learn, goes out to work every day as a street trader in the fruit and veg stalls of Dublin's Moore Street.

It's here she takes on the forces of darkness in the form of big business developers trying to take over her patch.

Along the way, Che Guevara in a dress meets up with a troop of blind trainee Ninjas, an alcoholic solicitor and a barrister with Tourettes Syndrome.

Christine Langan, who runs BBC Films Department, believes O'Carroll's effort will win over both sitcom and popcorn audiences.

"Brendan has a very good instinctive understanding of how to make the leap from the small screen to the big screen"

What most fans of Mrs Brown won't know is she has been carrying a film ace up her beige cardie sleeve since 1999 - when the first Agnes Browne ( she had an 'e' then) movie was made.

Starring Anjelica Huston (astonishingly) as the Dublin mammy, Brendan O'Carroll himself struggled to see how a future Morticia from the Addams Family could be passed off as a North Dublin housewife.

Nor could Brendan take over control of the writing. Hollywood, at that time, reckoned he didn't have the experience.

Yet, he has learned from his mistakes. He needs to have writing - and casting control.

And although in 1999 he hadn't played Agnes except on Dublin radio, since then he's come to realise she works best as a man dressed as a woman.

Comedy legend Stanley Baxter, one of the country's best ever cross-dressers agrees. "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. As for the film, it will work. O'Carroll is too clever not to make it work."

Comedy writer Ben Elton is also a Mrs Brown fan. "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."

O'Carroll has certainly incorporated enough silliness into the movie, but he's also well aware of the problems of context. He knows the sitcom world of Agnes is essentially the familiar kitchen/sitting room world. And he'll return to that as often as he can.

What Brendan O'Carroll has also learned from the first film adventure is Agnes Brown's world shouldn't be too dramatic, too Angela's Ashes. "I love a happy ending," he says.

Of course, the critics will trash the film before the trailers are up, as they have done the series. But O'Carroll is so confident he's already talking about a follow-up film.

D'DVD bargain bin? Not for a long time yet.

Brian Beacom is the author of The Real Mrs Brown: Brendan O'Carroll Story, out now in paperback. (Hodder, £6.99)

* D'Movie is released in UK cinemas on June 27.