The Weekend's Television: Emma, Sun, BBC1Monty Python – Almost the Truth: the BBC Lawyers' Cut, Sat, BBC2

Look under the bonnet

Emma Woodhouse, the opening of Jane Austen's novel tells us, is "handsome, clever and rich" and has lived nearly 21 years in the world with "very little to distress or vex her."

Things aren't nearly as easy for Austen purists, who tend to approach each new adaptation with a wary eagerness. Will it please or will it distress and vex, and if, as is more likely, it's the latter, how exactly is it going to do it this time? The answer, on this occasion, is that it begins by treating the novel as if it is a dark fairy tale. Austen's dry, marriage-broker's opening has been replaced with the line: "Emma Woodhouse was born with the sun shining to a father who always expected the worst" and it is delivered not by a female voice but a male one – Mr Knightley himself. The direction, by Jim O'Hanlon, is tartly knowing too, full of those self-consciously artful symmetries that make it clear that this is a modern kind of fable. It would not have been a great leap, gender of the voiceover apart, to imagine that everything that followed was going to take part in Wisteria Lane, not Emma so much as "Desperate Regency Housewives".

None of this need have been a real problem (read the opening sentences of Emma in an arch American accent and you can see that you might almost get away with such an approach). But it puts something of a premium on the transition between knowing voice and unknowing characters – the people in the story who, to quote the title of one of the best ever screen adaptations of Emma, are clueless. Sadly, the primary- colour brightness seems to have carried over into some the performances here, which are just a little too brittle and over-amplified. Michael Gambon is good and funny as Emma's father, absolutely inhabiting his solipsistic fretting about the hazards of life, but Romola Garai doesn't capture (or isn't given the chance to by the script) the sense of frustrated intelligence that makes Emma bearable on the page. What is Emma, after all, but an author manquée, trying to write the plots of other people's romances and naively unaware that a marriage is not necessarily "happy ever after". She needs to be a little thoughtless, but not so snobbishly silly that we dislike her too early, and the minxish self-regard of Garai's characterisation doesn't always make that possible.

There's another problem in the casting of Emma and Mr Knightley too. The difference between a 20-year-old and a 38-year-old in Austen's day was much greater than that distance today, and it isn't remotely acknowledged by the 10-year age gap between Garai and Jonny Lee Miller, who, despite a nicely underplayed performance, still carries too much of the seductive bad boy about him to be convincing as a surprising love object. You feel that Emma here would have spotted him at once as a perfect prospect, rather than wasting all that time in sublimated bickering. And that threatens one of the novel's great achievements, which is to educate us alongside its heroine. We need to be a little shamed with Emma, a little aware that we too have been carried away by fun and flippancy and lost sight of real values. But Mr Knightley is simply too sexy to be dismissed as old-fashioned, quite apart from the fact that Sandy Welch's script provides him with such an explicit early rebuke ("Harriet and Robert are not your playthings, your dolls") that only a complete airhead could miss the point.

Monty Python – Almost the Truth: the BBC Lawyers' Cut began with what we can now call a Pythonesque title sequence. Over an animation of global apocalypse someone sang a Bond-style theme tune: "It's a new documentary... it's not complimentary... but it's better than a hysterectomy". True on the first and last count, but not on the middle one, since this trot through Monty Python history was actually quite flattering to the programme and the people that made it, barring Graham Chapman, perhaps, who isn't around anymore to mind. In rock-band geneology style, it traced the past pedigree of a group that eventually came together with little more than a vague wish to travel in the same direction. "It was the worst interview that anyone or any group has ever done," said Cleese, describing the terrible pitch they made to the BBC. "I'll give you 13 shows, but that's all ," replied the commissioning editor, which was what passed for rigour in those days, and the rest – after the wobbly start that all truly innovative comedies have because they've got to teach the audience a new kind of funny – was history. The best bit was Cleese's curiously barbed attempt at long-distance teasing of Terry Jones. "What Terry's never been able to accept," he said earnestly, "is that the Welsh are a subject people put on earth to carry out menial tasks for the English".