In a way, I’m glad that Mrs Brown’s Boys (Christmas Day, 10.30pm, BBC One) exists, and that it exists for the people it exists for, because I realised something halfway through watching this year’s Christmas special (dire, like unrehearsed panto, just nothing redeeming at all about it, unless you are into having jokes spooned into your mouth like the last purée you eat before you die, in which case you’ll probably gobble it down the same as you always do), and that is this: the viewers of Mrs Brown’s Boys are also the people writing in to complain on the BBC’s Points of View.

I have literally no evidence to back this up other than a sincere, unshakeable, powerful gut feeling, so let’s just take it as fact: everyone who finds themselves too challenged by, like, same-sex dance routines on Strictly, are also the same ones who see Agnes Brown and go: “Yeah, she’s got a big mole on her chin, that’s sort of like a joke.” A substantial amount of the running time is just letting characters walk into shot, say a cheery “hello”, then get a round of applause from the audience. It’s safe here in Mrs Brown’s world, where the worst thing that can really happen is a Christmas tree falling over, or folk running out of teabags. Fine. Whatever. Let people who think The One Show is late-night TV have it.

But then: how to dig into the sheer fact that the Mrs Brown’s Boys special has somehow become the centrepiece of British Christmas TV? At the start of the decade we didn’t have this: the first special in 2011, managed around 6.6 million viewers; by 2012, the show was the most-watched programme on both Christmas Eve and Boxing Day, with 11.6 million and 10.7 million viewers respectively; 2013, 9.4 million; 2014, 9.7 million.

Something happened, sight unseen, and now Mrs Brown is as much a part of the Christmas furniture as The Snowman, the Queen’s Speech, a Pixar film occupying the 3pm slot on BBC One, and some sort of adaptation of a children’s book with an all-star cast doing the voices. This phenomenon makes me feel like an alien blasted to Earth from space, where everything is almost normal: you have the same foods you’re used to, the same traditions, the same routines, then for some reason at 9pm on Christmas Day you all sit down and watch a man in tights and a cardigan say “feck” 10 times in a row and think it is magnificent. Understanding the appeal of Mrs Brown’s Boys is not the job for a TV columnist. It’s for either an anthropologist or a criminal psychologist, or both.

Anyway, this is the premise for this year’s special: what if they made It’s a Wonderful Life with an Irishman in drag instead of Jimmy Stewart, and without all the lessons of It’s a Wonderful Life, or the heart and the artistry? Like, basically, what if someone who vaguely remembered reading the Wikipedia synopsis for It’s a Wonderful Life made an It’s a Wonderful Life-themed TV episode, and it ended in an impossibly strange Merry Christmas singalong with a clapping, adoring audience? What if that?

Well, that’s what it is this year. If you like Mrs Brown’s Boys, you’ll probably like it. If you don’t like Mrs Brown’s Boys, I don’t know. Have a nap or try and get a cheeseboard going instead.