The two things I hate most about Christmas are a) Advertland showing me how sparkly and joyous my home and bright-eyed kids are at this time of year, and b) the Doctor Who Xmas special telling me that if only I can open my heart and put cynicism aside, then I too can enjoy a mash-up of Dickens, C.S. Lewis and the Brothers Grimm, where daleks with tinsel round their guns exterminate the spirit of Scrooge as laughing children come pouring from the Ice Queen’s dungeon and something nice happens on a London housing estate. Or similar.

That’s what was so great about We’re Doomed! The Dad’s Army Story (BBC2, 22 December). With all the season’s comfort and joy but none of the mawkishness, it dramatised the delightful, cocklewarming story of how two middle-aged has-beens called Jimmy Perry and David Croft triumphed over adversity to create the greatest British sitcom of all time.

Well, I say ‘adversity’. I think if you’d been scripting it as fiction you might have come up with obstacles a bit more insuperable than the ones here: Jimmy being cruelly denied the chance to play the part he’d written for himself — spivvy Private Walker; BBC controller and ex-para Paul Fox being a bit sniffy about their use of the war for comedic purposes; somebody you’ve never heard of not taking the part that went instead to Arthur Lowe…

But the feebleness of the ‘jeopardy’ (as it’s known in the trade) was all part of its amiable charm. You really didn’t mind that Croft (Richard Dormer) and Perry (a perma-mugging Paul Ritter) had it so easy because they were clearly such likable fellows — the former a slightly crusty, well-organised major, the latter, a cheeky chappy ex-sergeant — and also, though little did they realise it at first, such comedy-writing geniuses.

Perry, a struggling ex-Butlins repertory actor, dreamed up Dad’s Army when the sight of a Guards band playing in St James’s Park reminded him of his wartime service. Croft was called in to polish and discipline the scripts. They got on like a house on fire. ‘We’d always see eye to eye,’ Croft once told me. ‘No, we never had a row. We couldn’t afford to. There was too much money at stake,’ quipped Perry. (This was for a big Dad’s Army number I did for the Telegraph a few years ago: look it up, it’s rather good. You’ll go: ‘How come James Delingpole doesn’t do nicely turned pieces like that any more?’ And the answer is: he bloody would if newspapers still paid for them.)

I suspect it may partly have inspired Stephen Russell’s jaunty screenplay. It was all in there: bearded head of comedy Michael ‘Dark Satanic’ Mills insisting on the casting of John Le Mesurier because ‘he suffers so well’; Arthur Lowe telling Croft at his audition, ‘The sort of programme I hate is Hugh and I’, apparently unaware that Croft had produced all 80 episodes; Arnold Ridley getting bayoneted in the arm in the trenches, writing The Ghost Train but losing everything because he sold the rights, and having to spend his twilight years giving us Private Godfrey. (‘Throughout my childhood we were extremely strapped financially,’ his son Nicholas told me. ‘That £62 he was suddenly getting per episode completely transformed his life. It gave my father and mother the financial security they needed in their old age.’)

Not that I’m complaining, if my article was the inspiration. It was such a joyous, life-affirming drama, I sat through it, grinning from ear to ear. The acting was mostly superb. I’m not sure Julian Sands’s Le Mesurier was quite there, but some of the cast — notably John Sessions’s Arthur Lowe — were so uncannily like the real thing it could almost have been a documentary. But what really made it for me was the sense of period and place: cautious, buck-passing BBC apparatchiks in their small, dingy offices, fearful of committing to anything lest they be associated with failure; that almost unbridgeable gulf between the long-haired flower-power generation and their psychedelic music on the one hand (which gave us the most fantastic soundtrack, by the way) and on the other those who’d been through the war just over 20 years before. If your child has ever tried to show you how to use Snapchat, you’ll know exactly how it must have felt.

Was there really any danger that Dad’s Army was going to be shelved? Well, it makes a better story, I suppose. But it seems to me that everything about that series was so right — Bud Flanagan’s theme song, the exquisitely observed nuances of the English class system (such as the memorable episodes when Sgt Wilson discovers he’s an Hon., and the one where it is discovered that Mainwaring isn’t actually entitled to call himself Captain: ‘don’t tell him, Pike’), and so on — that the idea of it having been stillborn is just inconceivable.

Can’t say I’m looking forward to the remake, though. Why???