Brendan O'Carroll on Mrs Brown's Boys and "smack-on-the-bum funny" sitcoms

His privacy is helped by the fact that he is burly, moustached and very masculine, qualities that Mrs Brown admittedly also shares, although O’Carroll is bald and has the chest of a rugby player, while the Dublin widow he plays has a firm permed helmet of hair and a bust that resembles two rugby balls.

O’Carroll will be wearing the wig and prosthetic chest on television again tonight, although he may be sweating more than normally inside them as this is the first Mrs Brown’s Boys to be screened live, as one of the BBC’s events to mark this month’s 60th anniversary of the first TV sitcom, Hancock’s Half-Hour.

Performers in recorded shows often feel terror at the prospect of transmission without a safety net, but O’Carroll has 16 years’ experience of playing Mrs Brown on stage.

“At the start, I only ever saw the TV programmes as a half-hour advert for the live show,” says O’Carroll. “So, when we sat down to plan the live TV edition with the BBC, the producers and management were excited but quite nervous about it. But we said: ‘We do this almost every night!’ So the elements of pressure, performance and live audience are all familiar to us.”

Such is the theatrical demand for the foul-mouthed matriarch that O’Carroll now lives in Florida, calculated to be the most convenient base for stage tours: “A lot of the work we do is between here, Canada, Australia, New Zealand, Ireland and the UK. With the exception of Australia, which is 15 hours away, we’re no more than six hours away from anywhere we perform. So it’s a nice central spot to be.” At the time O’Carroll is speaking to me, there is some fuss over Adele having sworn repeatedly during the live BBC coverage of Glastonbury. “Oh, how dare she! How dare she!” he interrupts in his most scolding Mrs Brown voice.

The actor had assumed that the live edition of Mrs Brown’s Boys would be subject to a five-second transmission delay, a device used, for example, on radio phone-ins, to prevent libellous or offensive comments going out. But the live Mrs Brown, the BBC told him, will not have this technological prophylactic.

O’Carroll recalls the conversation: “I said, ‘Oh!’, because I know what I’m going to do out there, but I don’t know what Mrs Brown is going to do. So we’ll just have to wait and see.”

In referring to the woman in the third person, O’Carroll follows the practice of another cross-dressing comedy actor, Barry Humphries, who always allows Dame Edna Everage a separate existence. “Agnes feels separate from me,” O’Carroll explains. “I once heard a ventriloquist on TV, talking about the puppet as if it was real. And I used to think: that’s bull***t. But actually the character does take you over. I have very different opinions to her. Mrs Brown has that ‘me hip is going to go any minute’ walk. And the moment I start to do it, I’m her. Also she’s the type of woman who you never quite know if she’s going to hug you or hit you. And probably the clue is in the speed that she’s walking towards you.”

Despite the possibility that the character will surprise him live on air, he insists that the BBC has placed no restrictions on the live edition, not even insisting that he stick to an agreed script and avoid ad-libs. “I think it’s because I’ve seen a transition. The first ever script meeting with the BBC for series one, one of the executives asked: ‘Who’s Bob? There’s someone called Bob who’s in it quite a lot but he doesn’t seem to have any lines.’ And I said: Bob who? And he pointed to the script. And what I do is put in brackets after a line ‘[BOB]’, which means Bit of Business.”

This means that, between hearing the phone or the front doorbell and answering it, Mrs Brown would do some kind of funny look or movement. “And they said, ‘OK, and what will that be?’ And I said, ‘I don’t know.’ And they said, ‘And when will you know?’ And I said: ‘When the doorbell rings.’ And they said, ‘Oh, dear.’ But, by the end of the second series, they were saying: ‘We’re just going to trust you on the Bobs.’ And that’s a great trust, which I try not to betray.”

O’Carroll writes the bits between the Bobs from midnight to 6am in his Florida living room. He types a few lines and then acts out the conversation. “I do all the characters. A couple of times, my wife has come out of the bedroom and said, ‘Who are you talking to?’ And I’m in the sitting room doing a chat between three different characters.”

They don’t yet know the exact length of the live show but, if the written script comes in at 26 minutes, O’Carroll expects to leave three minutes for Bobs. The only change from the usual arrangements is that, to help with timings, he will be able to hear the production gallery, in the way that newsreaders do. “There has been a suggestion that Mrs Brown should wear an earpiece for this one. So I’ve written that into the script.”

The inclusion of Mrs Brown’s Boys in a celebration of great sitcoms will surprise those critics who suggest that it should be taken off air after the pilot episode. Does O’Carroll take pleasure in proving them wrong? “No. You have to accept the bad reviews. Sometimes you might even think, ‘Maybe we could learn from that and do it differently.’ But when people are questioning the entire principle of the thing – saying that a programme watched by 12 million people shouldn’t be on TV at all – I have no time for it. The object is to make people laugh. And, if ever Britain needed a laugh, it’s right now.”

Has the BBC really never asked him to watch his mouth on air? “I do get told sometimes to watch the swearing. And I always say: I wish you hadn’t told me because now I’m going to do it. When we started, I always expected to have the f*** meeting and they called me in and said that if I stopped saying it, they could put the show on earlier and make me a big star. And I said I didn’t want to be a big star and so we’d make it as we wanted and if they had to put it out at 2am, then so be it.”

His own picks from the history of sitcom, though, are not series that needed a bleep machine. “Only Fools and Horses is the most brilliant thing ever written apart from John Cleese’s Fawlty Towers. I also love Dad’s Army. They just make me laugh.”

These choices of character-led family favourites are pointed, revealing O’Carroll’s manifesto: “Somewhere along the line, TV comedy, instead of being funny, became clever. Clever was suddenly good. So I feel that, when Mrs Brown came along, it resonated with the audience comedy had forgotten: smack-on-the-bum funny, no message, no sad ending.”

Mrs Brown's Boys Live: Saturday 9.45pm BBC1