Downton Abbey
ITV1

Two weeks in, and those of us who have been longing for a Brideshead Revisited-style Sunday-night treat - for a drama that is long, sumptuous and properly involving - must now invest all our hopes in the BBC's forthcoming revival of Upstairs, Downstairs. Yes, I refer to Downton Abbey (Sundays, 9pm), an advert for which I was even treated to at a cinema the other day. How is it that this much-hyped series has turned out to be such a disappointment? I was determined to love it and, after struggling to feel even remotely involved during part one, I decided to keep my doubts to myself. Perhaps it would pick up. Yes, I felt patronised by the explanatory dialogue. Yes, the soundtrack was intrusive. Yes, virtually every costume-drama cliché one can think of had been concertinaed into a little over an hour's worth of television. But, still: a grand house, a collection of warring servants, an estate without a rightful heir. What's not to like?

Yet, now that I've seen part two, I'm already thoroughly sick of the bitchy servants and couldn't care less who inherits Lord Grantham's pile. If they turned Downton into timeshare flats, I'm not sure I would be exactly sad. Julian Fellowes, who won an Oscar for his script for Gosford Park, another big-house-in-changing-times drama, is obsessed by social class and I think Downton Abbey is a victim of that fixation: the series has no light and shade because its only preoccupation is where anyone stands in the house's hierarchy. As a result, everything else - plot, character - has been bleached out.

People are either good or bad, nice or nasty: cardboard cut-outs in jet beads and plus fours. The whole set-up feels ersatz, a mere vehicle for gawping at silverware and hunting jackets. Worse, for all that Fellowes pays lip-service to the social revolution that will come with the Great War - his working-class characters say things like "Just because you're a lord, you think you can do what you like with me!" - the script oozes nostalgic approval for the days when people not only knew the difference between an earl and duke, but cared about it, too.

So, in terms of emotional development, his characters make some weird journeys. Lord Grantham's heir, Matthew Crawley (Dan Stevens), who is a solicitor from - the horror! - Manchester, learns to love his new valet, allowing him, against all his instincts, to fiddle with his cuffs and brush down his lapels, and this is deemed a Good Thing. Order is restored, and Crawley is a better man because of it. As for me, I demand greater epiphanies than this from a drama that expects to be taken seriously.

Much has been made of Downton Abbey's wondrous cast. Hmm. Hugh Bonneville as Lord Grantham and Elizabeth McGovern, who plays his rich American wife, Cora, are wonderful; neither one of them could overact if they tried. Bonneville is able to convey powerful emotion with the twitch of a corner of a lip. But Maggie Smith is woefully miscast as the dowager countess. What kind of countess sounds like the bastard child of Alan Bennett and Frankie Howerd? She's hammier than a plate of Christmas gammon. I like Rob James-Collier as the sculpted footman Thomas, but you knew he was going to turn out to like boys right from the off, just as you might have predicted that the doctor at the local hospital, an establishment funded by the good earl, would be Scottish. Edwardian TV doctors are always Scots.

What is going to happen? Oh, must I? I expect that Lady Mary (Michelle Dockery), the earl's eldest daughter, will, after various disastrous flirtations, fall for her cousin, the good solicitor from Manchester, perhaps breaking her younger sister's heart in the process. The estate will be safe. The servants will continue to be uppity to no great effect. The countess may well enjoy a long deathbed scene, just like Lord Marchmain in Brideshead. You see, Downton is not a place for surprises.

Perhaps that is the point. This is status-quo television, uncomplicated and undemanding, with backstories that are easily tied up between ad breaks. You can watch it with your supper on your knee without any fear that your tray will have cause to wobble.