Many of them involve Music and Movement. I searched vainly on the BBC website for any evidence that Music and Movement still bends and stretches and skips its way through modern childhoods, but the nearest I can get is Dance Workshop and something likely-sounding called Hop Skip and Jump. And since these go out on Radio 3 in the wee small hours, along with Mr Grumpy’s Motor Car, Mental Maths 3, Scottish Resources and stories from Guru Nanak, I don’t tend to hear them. In the old days, before cassette recorders with timers, schools programmes went out in the afternoon on a Radio 4 wavelength, enabling nostalgic adults to sit in their cars shouting out the answers to Mental Maths and singing along to “Three little speckled frogs”. Now, like so much in education, they are hidden from curious onlookers.

But the role of Schools Radio in bygone education was huge: possibly more significant even than video and film are today. I can still remember verbatim long passages from the schools broadcasts of my childhood, but none from film or TV. I can remember a song called “Farewell Manchester” which was made much of in the music programme Rhythm and Melody, and if I know all the words to “D’ye ken John Peel” this has nothing to do with any hunting background and everything to do with BBC Schools. And as for Music and Movement, to this day if that commanding lady’s voice were to say, “Now find a space - and sit in it!” or “Make yourself into a long shape!”, I would immediately do so, casting dignity to the winds and ignoring all middle-aged twinges. The programme stopped in the Eighties, after 30 years, but I bet that if you were to pipe it into any pinstriped office today at moments of stress you would get countless greying, red-faced men bending their pinstriped shapes into Giant Steps, obediently bunny-hopping, or curling up very, very small. It had authority. I have long suspected that this is how Lady Thatcher acquired such mastery over her Cabinet.

The thing about Schools Radio, as against schools TV, digital CBeebies, Online Curricula and all the rest of the modern razzmatazz, is that it demanded absolute silence and concentration. The big radio - at my first village school it was a walnut-cased monster with red valves glowing in its innards - focused attention. Whether it was a drama about Vikings, a poetry reading or a singalong, it was something too precious and fleeting to be wasted by Alfie Knights making rude noises or Keith blowing his nose incessantly. Round that radio, we all behaved.

And we concentrated. The ability to listen, without visual excitements, is something extraordinarily valuable, and in a noisy world it is the radio (and its sidekicks, story-tapes) which can give children the best chance of learning that skill for later use. Sometimes, it was the worst kids who listened most reliably to Schools Radio in the classroom, because it was different from a teacher just droning on. The teacher was a foe, an authority-figure, to be baited. The radio voice was disembodied, unbaitable, wouldn’t know or care if you didn’t listen. So you probably did.

When I was a young studio manager in training, I used to love working on Schools. The dramas were brief and comprehensible; the imagination of the producers considerable. One of my favourite moments was when the senior operator present couldn’t think of a way to convey the look of the Albert Bridge at night with occasional bulbs out: we needed to play music with sudden, popping drop-outs to give the feeling of interrupted light-strings. Fresh from my training course, I invented a way, by clicking a tape destination switch in and out. It sounded like the bridge looked: perfect synaesthesia. I am proud to think that somewhere out there there are adults who remember the Albert Bridge Song, and others who were stirred to the idea of a trotting horse by my adroit manipulation of coconut-shells, or who shivered in sympathetic cold when I turned the handle of the wind-effects machine in the programme about Scott of the Antarctic .

Radio is a psychological miracle. It conveys wonders, yet the real wonder of it is inside yourself, aged seven or so: the ability to be still, listen and imagine and dwell in a parallel world, free of your wriggling body for once. Magic.

“Radio, A True Love Story” by Libby Purves is published by Hodder, pound;14.99