It began with the sinking of Titanic and the loss of not one but two heirs to the title. James Cameron having already filmed this disaster, the producers of Downton Abbey were spared the expense of re-enacting it. Last week another Hollywood blockbuster was in viewers' thoughts as the most iconic scene from Alien was re-enacted at the Downton dining table. His Grace’s ulcer burst on scene in a lurid shade suggesting Crawley blood is less blue than previously supposed.

It's been the most heavily signposted illness in drama history. A twinge here. An "Oof" there. Chekhov's roiling guts. And tonight, His Lordship's mystery complaint finally took centre stage, in a scene that led one to wonder exactly how to remove three pints of aristocratic blood from a pristine white tablecloth.

It began with the sinking of the Titanic all those series ago. However many holes Julian Fellowes has seen fit to build in to the design, his own ocean-going liner has valiantly refused to go down with all hands on deck. But by Christmas we will have seen the last of Lord Grantham and his household, until such time as they all get resurrected for a big-screen reunion, even the Dowager Countess Maggie. For some, the bereavement will be too much and they'll rewind to the start of the first boxset. For others it'll be like the end of a long prison sentence.

The world now knows him as Lord Crawley, stiff-backed in white tie and tails, regimental garb or, for relaxation, tweed. But before he became the face of Downton Abbey – and of bumbling institutional incompetence in Twenty Twelve and W1A – Hugh Bonneville could be seen in roles of considerable depth and range, including a moving Philip Larkin and a brutish husband in the BBC's Daniel Deronda.

“But I do want to be stuck with you.” Five series and five Christmas specials down, Downton fans heard a line of dialogue they had no idea they’d been waiting for all this time. Never mind that the scenario was a straight lift from The Remains of the Day, in which the stuffy old butler proposes to the starchy old housekeeper. Stone the crows and knock us all down with a feather, Carson popped the question to Mrs Hughes. And what, of all the wonderfully blindsiding things, did she say in reply?

It won’t come as much of a surprise to find that the staff at Tatler are a bit on the posh side – who’d have thought? – but I honestly doubt they’re that much posher than, say, those at The Times, or The Guardian, or that other esteemed people’s champion, the New Statesman. As for the “posh to common” ratio on theartsdesk – without doing an exact head count, I’m not sure we radically break the mould, either. Such is the way the world rock ’n’ rolls in class-ridden Britain. 

On and on the stately galleon sails. The fifth wodge of Downton Abbey has been light on utter knuckle-gnawing preposterousness. Plots conjured up at random from thin air have been in slightly shorter supply than usual. The very worst you can say of it is that Lord Fellowes is no Agatha Christie. The poor old blighted Bateses have now been subject to a matching pair of cack-handed murder mysteries. To get accidentally banged up once in a slow-moving crime plot may be counted a misfortune. Twice looks like cluelessness.

A year ago it was all so different. Lady Mary gave birth and on his way home from the delivery suite Cousin Matthew steered his vintage soft-top into a tree trunk. There's rather less to report from Downton Abbey (***) this Christmas and the Daily Telegraph is free to devote its Boxing Day front page to something else. No actor has asked to be written out of the series, no one got engaged or even kissed, no one ended up in prison or even tears. His Lordship came dressed as Santa Claus, although he claimed to be wearing the uniform of a Lord Lieutenant.

So, another series down and what do we know? First up, until this final episode no one had died either by contractual agreement or Fellowesian godlike decree. We’ve had a rape, an unwanted pregnancy, a near abortion, a mysterious disappearance and a spot of senile dementia. Plus not one but two uppity colonial singers have drifted upstairs. If it weren’t for the vowels and the coat-tails, this could be Emmerdale, tackling urgent social issues in a Yorkshire accent and congratulating itself on the column inches the morning after. Why else all the animal husbandry?

"The price of great love is great misery when one of you dies," intoned the Earl of Grantham lugubriously in this fourth-season opener [****], and the death of Matthew Crawley hovered heavily over the household. His widow Lady Mary haunted the corridors like the Woman in Black, speaking in an even more dolorous monotone than usual. The great Penelope Wilton imbued Matthew's mother Isobel with a piercingly real sense of grief.