My Zinc Bed, BBC2<br/>Mutual Friends, BBC1<br/>The Last Word Monologues, BBC1<br/>Super Botox Me, Channel 4

A fine adaptation of a David Hare play only serves to expose the poor quality of scripts produced especially for the small screen

Sometimes you get glimpses of what TV could do, how good it could be. Jonathan Pryce had a speech in My Zinc Bed that was as beautiful as shivering mercury. "It's the autumn air. At summer's end, there's always a moment of calm. A slight change in the air. It's still August. The sun beats down. But it's touched with the knowledge of what's to come." It was like he had stepped into my living room and looked out of the window. The elusive, wriggling here-and-now had been trapped, still-breathing, in the net of the dialogue. The words felt as if they'd been written that day.

In fact they were written eight years ago, for the stage. It's embarrassing, really. This was the best writing on TV this year – not that particular quote, but the whole drum-tight, reverberating little play, and it wasn't even written for TV. Something has gone awfully wrong with purpose-built TV dialogue and the sheer quality of David Hare's writing – textured, poetic, packed with ideas – showed this up, line by line. My Zinc Bed wasn't a technical triumph – exterior London skies (cloudy) hopelessly mismatched against studio skies (blue) – but it was well written and that, in the end, is all that really matters. The script's the branch the birdies land on. Uma Thurman was at her leonine best, every syllable of her Mitteleuropean accent ringing true on the tinkling love triangle of the play. She was not, we think, doing it for the money.

Compare and contrast with Mutual Friends, a shudderingly badly written new TV drama that wouldn't last beyond the first week in a theatre. On TV it'll carry on for six godforsaken episodes. It is one of those vaguely unpleasant pieces that thinks it's a black comedy but has neither the charm nor the cruelty to pull it off. People shitting in other people's shoes? Hilarious, I'm sure. The soundtrack – a knowing, jaunty tango – amplifies every failing. The estimable cast – Marc Warren, Alexander Armstrong – have a vaguely betrayed air, as if they know the script can barely cover their naked shame. Only Keeley Hawes has thrown her heart into it, seeming to relish her shallow, unappealing character. I used to really like her as an actress. One line for me sums up the poverty of this script. A poor child actor had to deliver a bombshell about his parents' infidelity. He was only a kid but he still seemed to cringe as he said the words: "Is Uncle Carl in heaven? Good. Now he won't be able to shag mummy any more." Can you think of a smarmier, more contrived line of dialogue? A more obvious plot-hinge, a cheaper, nastier, less plausible sentence for a child to deliver?

The Last Word Monologues by Hugo Blick were a good attempt to infuse some theatrical confidence into TV writing, but ultimately failed to captivate. While I love the idea of a slowly unfurling soliloquy, I found myself desperately bored by the self-indulgent pace and mawkish tone of these. They felt like first drafts, rough and tumbling, when the tightrope walk of a monologue requires a more precise discipline.

Rhys Ifans plodded through his half-baked sub-Brokeback Mountain script, while Bob Hoskins's sentimental gangster was a sophomoric cliché. Sheila Hancock's woman waiting for euthanasia could have shuffled off a lot quicker as far as I was concerned. Alan Bennett has set dizzyingly high standards for the modern TV monologue and these did not come close.

Intrepid TV journalists need something to investigate. Fortunately most of them have egos that take a long time to explore. Kate Spicer took a gruelling journey into hers in SuperBotox Me. She gamely tried every injection, peel and chemical procedure going, enquiring at each step exactly how it made her feel, which was usually a little bit better and as well as a little bit worse. She often tired along the way, exclaiming "I'm sick of thinking about my face!" and "Enough fannying around!" (couldn't have put it better myself), but kept on trudging on till she had literally cried tears of blood. Gruesome, compulsive viewing.