The Weekend's TV: Young, Dumb and Living Off Mum / Sun BBC3<br/>Orchestra United / Sun Channel 4<br/>Amish: Squarest Teenagers in the World / Sun Channel 4

Some mothers do have them

Mother love is all very well in moderation, but if you overdose, the results can be appalling, as Young, Dumb and Living Off Mum is currently demonstrating. Curiously, although a complete numbing of the faculties of self-examination is one of the symptoms of mother-love poisoning, at least one of the victims here appears to have correctly diagnosed what's gone wrong: "My mum's 100 per cent responsible because she's created me and she's created a little monster," said Caron, conveniently exempting himself from the tiresome business of behaving well. And if his analysis of the situation struck you as a little unfair on his mother (surely the absent father had to shoulder some blame), you may have thought again when you watched her later, fondly defending his successful attempt to defraud a local shopkeeper.

If you haven't seen the series before the premise is simple. A group of grimly spoilt young people – amoral, indolent, stupid and aggressive – are cut away from their support systems and forced to fend for themselves. They have a limited budget and are required to go to work to earn it. Each week, the most resistantly feckless is sent packing by an assembled council of their parents, with the brat who survives longest winning a round-the-world trip and, just possibly, a ticket to independent adulthood. Last week, one of them stalked off in a huff because she couldn't bear living with "chavs" anymore and another was expelled for a violent tantrum, so this week numbers were filled out with a new arrival.

Marc, a sleazy parasite who likes to think of himself as a playboy, was hoping for a good-looking girl. He got Duane, a cosseted teenager who collects Disney dolls and has two chihuahuas called Princess and Paris: "Now we've got another mincer in the house," said Marc gloomily, adding homophobia to his already extensive charge sheet of social vices. They were then all sent off to Whipsnade to work as zoo-keepers, a task that fully explored their infantile sense of humour and whining incapacity to endure even the smallest amount of discomfort.

They are not all as bad as each other. Dim glimmers of light are visible, little sparks of self-knowledge and aspiration. But then they pull out the vodka and before long they're all having a screaming match on the stairs. Having only ever seen themselves reflected in the flattering, indulgent mirror of their parents' eyes they clearly have no idea how ugly and dim-witted they look. One of them even shouted: "Do you think I'm bovvered?" I'm glad to say that Marc got the boot in the end, at which point his mum threw a defensive hissy fit, making it clear that there will always be a space for him somewhere, however spectacularly he wastes it.

British youth came out looking marginally better in Orchestra United, a series in which the conductor James Lowe is attempting to mould a group of teenagers (with musical ability but no orchestral experience) into an ensemble fit to play a public concert. In the first rehearsals, this looked about as doable as training up a Blackpool donkey to take part in the Grand National, but – after a week away at a residential course – they just about passed their first test, a private concert for friends and family. The results bore the same relationship to a professional performance as cottage cheese does to double cream, but you could at least tell that it was some form of dairy product, and the prospect of further improvement didn't seem impossible.

Obviously, this lot are in a different league to the hand-picked losers of Young, Dumb and Living Off Mum, but even here the sense that your teenage years are a childhood with extra liberties, rather than any kind of prelude to adulthood, was pretty strong. The trumpet section proved particularly ill-disciplined, mucking about so much during rehearsals that Graham, the motivational coach, had to be brought in to give them a stiff talking to. His idea of stiff was my idea of floppy, to be honest: "I don't want to sound too harsh," said Graham, explaining that they might get kicked out, "but that is the bottom line." He virtually apologised for asking them to think about the other players. Anyway, harshness, or Graham's hopeless decaffeinated version, seemed to do the trick.

The Amish visitors in Squarest Teenagers in the World have been surprised by how childish British teenagers are, but that's possibly because most of them are 18 going on 65:"I think God hates low necklines," said one of them, when the subject of modesty came up. Another gravely explained that rock music kills plants when it's played to them and contains satanic messages if you run it in reverse.

This week, they were staying with a middle-class family in the countryside – lively, thoughtful and considerate teenagers who introduced them to the dangerous pleasures of sea-bathing and music festivals. Becky was troubled by the rhythm of the music: "It does something to your body that I don't really like," she explained quietly. I think what she didn't like was that she quite liked it, because later, after checking through her Bible for scriptural authority, she had a go at dancing. She also worried about her host's lack of faith: "It's really a burden to me," she said, "because I don't want those nice people to go to hell." I think Marc should be sent to live on an Amish farm for a year or two. He'd learn something about seemliness.