Downton Abbey: The Finale, ITV1

Defying predictions that there would be no audience for a period costume drama set in an Edwardian country house, Downton Abbey has become the TV event of 2010. Episode one notched 11.6 million viewers (including repeats and ITV Player viewings), while episode two edged up to 11.8 million. The concluding episode seven threw all the cards in the air, blowing apart Mary and Matthew's romance, leaving Anna and Mr Bates dangling in limbo, and ending with the shattering news of Britain's declaration of war on Germany. There was even, briefly, a pregnancy for the fortysomething Countess of Grantham. 

The anguish of fans at the prospect of the first series coming to an end has been at least slightly assuaged by the news that a second series has already been commissioned, and overseas markets are battering at the doors of production company Carnival Films to get their hands on it. If Downton Abbey hasn't yet trounced The X Factor in the ratings war, it may none the less represent a watershed in British television. It has emphatically whipped the carpet out from under those who have tried to dance on the grave of quality TV drama, and ITV's chief executive Adam Crozier is even talking about Downton as his spearhead in a drive to take the network in an artsier, more drama-orientated direction.

As the first series completed its run, four writers on theartsdesk explain why, in their view, the series has worked so well, and also nominate their favourite upstairs character (excluding the Dowager Countess of Dame Maggie, who will no doubt be walking off with the Bafta), favourite downstairs character and, in a series full of them, the most far-fetched plotline. We urge you to join the debate and make your own nominations in the comments section.

Adam Sweeting:

It's odd that Downton Abbey's writer, Julian Fellowes, has been complaining about criticism of the show from "the Left", since a lot of it seems to have been on the letters page of The Daily Telegraph (the stuff about double yellow lines on the road and visible TV aerials). But the salient fact is that viewers are engaging intimately with Downton Abbey, to a fanatical and nitpicking degree, in a way which surely makes a nonsense of party lines, despite some kneejerk moaning about "toffs".

Indeed, this is where the true cunning of Fellowes's conception lies, since his masters-and-servants microclimate within Downton Abbey is inextricably linked to events in the world outside. It's true that the show is riddled with anachronisms - the Earl and Countess of Grantham would make fairly liberal-minded parents even in 2010, their politically radical daughter Lady Sybil always looks as if she's off for a weekend at Glastonbury, and even Maggie Smith's pantomime dowager has a heart, although perhaps not of gold, behind that facade of withering haughtiness.

But what makes the drama grip is the way that irresistible social and political change is ticking away like a bomb buried under Downton's manicured lawns, whether it's the Irish chauffeur with a passion for socialism or the rise of the middle classes represented by cousin Matthew. And every character and storyline is overshadowed by the knowledge that this entire world is about to slide into the volcano of the Great War.

Favourite upstairs character? Robert, Earl of Grantham (Hugh Bonneville), a man of superhuman tolerance and reason.
Favourite downstairs character? Anna, the head housemaid (Joanne Froggatt, pictured above right), outwardly gentle but inwardly tough as old boots.
Most far-fetched plotline? Thomas the footman's gay conspiracy with the Duke of Crowborough to steal the Downton inheritance.