One, two, three, four! Hi-5!” Anyone with children under five will need no explanation here. Pitched somewhere between Steps and Nazi marching anthems, it’s the theme tune to the infants’ show Hi-5. Sing it in German and shudder at its efficacy. But, of course, Hi-5 aren’t trying to get your children to invade Poland – that would be tricky to do from Australia, the show’s home country. No, they are trying to physically enliven the usually passive process of watching telly and dispense musical life-lessons.

It gets better if you watch Lazytown, but only as long as you turn the sound off. The show’s best intentions – rebranding fruit as “sports candy”, telling you to keep active – are undermined by a series of songs called the likes of Bing Bang and Energy, prolonged exposure to which leave you feeling as if you’ve been dragged up a dark alley and mugged by Aqua. So much for the healthy mission statement. If music was food, Lazytown would be mostly sugar and tartrazine.

Similarly, CBeebies’ music and movement show Boogiebeebies thumps away at the adult cranium like the Muzak in a lift that stops only when it gets to a wing of hell staffed by Scientologist personal trainers.

They don’t write children’s TV music like they used to. They literally don’t. The stuff that today’s thirty and fortysomethings grew up to was a marriage of convenience between avant-garde musicians ( Picture Box, The Clangers), left-leaning folk music enthusiasts ( Bagpuss, featuring that enduring metaphor for the proletariat, the mice on the mechanical mouse organ) and experimentally minded classical musicians. One of the latter, Freddie Phillips, was responsible for giving Camberwick Green and Trumpton their gentle musical character.

A few years before his death, Phillips explained to me exactly how he set about writing the Camberwick Green music. He made Brian Cant sit in a cupboard lined with egg boxes to sing Peter the Postman’s song, and then – seeking to do “something special” for the programme’s main theme – he experimented with tape speeds and backwards clockwork noise to create a two-minute welcome comprising three mesmerising mini-suites. Far from bemoaning the restrictions under which he was forced to create this stuff, Phillips maintained that it was essential to the process. He also intimated that – had he thought he might get away with it - he might have gone farther. He advocated that young children should be weaned on a diet of Boulez and Stravinsky. Even if parents couldn’t stomach it, Phillips said they owed it to their offspring.

One voice that chimes in agreement with Phillips is that of Jonny Trunk. Over ten years as boss of Trunk Records, he has slowly assumed the role of a pop culture National Trust – preserving musical memories that will always be too obscure for mainstream consumption. Under his guidance, Vernon Elliot’s original scores for The Clangers, Pogles Woodand Ivor the Engine have all appeared on CD for the first time.

If you remember watching any of these shows at the time, you won’t remember thinking that your horizons were being broadened. Which, according to Trunk, is precisely the point. “You weren’t thinking. You were absorbing! I think there’s a fear of melancholia in modern kids’ TV. And melancholia is nothing to be scared of. If you drive to a rainy Welsh market town at 3pm on Wednesday, just as half-day closing is kicking in, that’s how the music to Ivor the Engine sounds. I feel that, by showing me that market town through notes and chords, way before I could actually see it, Vernon Elliot’s music made me a better person.”

For Trunk, all this used to be mere theory until he, the father to two-year-old Fingerbobs fan Bert, took matters into his own hands and helped to start his own music and movement class for children in West London. Favourites, apparently, among the children of W10 are two of the most terrifying TV themes of the past 50 years: Delia Derbyshire’s Dr Whotheme and the chloroform dream-haze of Maneche, Jacques Lasry’s theme to the educational show Picture Box. The idea that some commissioning producer deemed Lasry a fitting candidate boggles the modern mind.

Lasry and his associates, Bernard and François Baschet, were fascinated by the idea of blurring the distinctions between sculpture and sound. The Baschet brothers built musical sculptures, one of which Lasry plays on Maneche. François Baschet explained their rationale: “In our present-day computer-card civilisation,” he declared, “the public must find new ways of expression.”

According to Trunk, the best children’s TV music is an imperfect fit between what the audience thinks it wants and the people who are around to provide it. Folk musicians ended up providing music for programmes such as Play Away and Bagpuss because the sort of people who went to folk clubs in the Sixties were BBC producers.

“That’s how I got the Play Away job,” says the kaftan-attired folk pin-up Toni Arthur. “The producer actually ran a folk club in Ealing and I used to sing there. I turned up for the audition in a miniskirt and pink thigh-length boots. I think that endeared me to them.”

She adds, not unreasonably, that “children felt I was someone they could take home, but also I was a bit naughty”. But for the ultimate interface of folk and kids’ TV, Bagpuss continues to reign supreme. Sandra Kerr was responsible not just for the voice of Madeline the rag doll, but the mice. She remembers the Bagpussco-creator, Oliver Postgate, “arriving with his stories and the rest of us all playing along in a stream-of-consciousness session.

“The best bit was recording the vocals for the mice. It involved singing very high but slowly, so that the tape could be speeded up. You can hear us giggling as we sing [to the rune of Row, Row Your Boat]: “Nose, nose, close your nose/ What a dreadful pong/ Stinkily stonkily pingily pongily/ What a smelly song.”

Bagpuss’s influence on a future generation of songwriters was formalised some years ago, when Radiohead approached Postgate – a man with strikingly similar political leanings (his father founded the UK Communist Party) to the band’s leader Thom Yorke – to direct the video for There There, in 2003, a song which, on the album sleeve, references the Bagpuss tune The Bony King of Nowhere. Old age forced him to decline.

Perhaps it stands to reason that a generation that, like Yorke, was exposed to Elliot, Jacques Lasry and the Bagpuss gang over here, and Sesame Street, The Muppet Show and Charlie Brown in the States, is slowly beginning to steer children’s TV music back into less stagnant waters.

The composer John Greswell was enlisted by Lauren Child, the creator of Charlie and Lola, to come up with the music for the TV series and accompanying CD. The first thing he did when embarking on the project was to enlist the help of Pete Wareham and Seb Rochford, from the Mercury Music Prize-nominated outfits Polar Bear and Acoustic Ladyland, both groups whose music suggests more than a hint of Clanger in their collective DNA.

Greswell then had to find a way to make an album featuring the voices of Charlie and Lola that didn’t get on parents’ nerves. “Children singing has limited appeal,” says Greswell, “pushing this sort of enterprise into the realm of novelty.”

So he used elements of the shows’ dialogue as springboards from which the players could go on to create. Almost uniquely among the pantheon of modern kids’ TV spin-offs, the results don’t want to make you impale the palm of your hand on the gearstick.

Thanks to Charlie and Lola and Nick Jr’s latest creation Wonder Pets, my kids are finally moving away from Hi-5 towards the daily adventures of a tortoise, a duckling and a hamster who act as a self-styled emergency service to distressed creatures all over the world. What distinguishes Wonder Pets from other programmes of this sort is that every episode takes the form of both well-known and original operettas, conducted by a live orchestra overseen by the Grammy-winning producer Jeffrey Lesser.

In the words of its executive producer, Josh Selig, “It helps it to resonate beyond just those years that [children] are watching that show”.

He’s absolutely right, of course. And even if it does mean that, for the rest of their lives, my daughters may still think of an anxious baby swan singing, “I trip or bump into a tree” when they hear Swan Lake, it’s a small price to pay.

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