Don't confuse the respective battles going on in BBC Radio at present: the issues on which they turn are very different. The English- language operations of the World Service are being merged with their domestic counterparts, for reasons of mere bureaucratic neatness; the results will be more expensive and - for Bush House's 35 million overseas listeners - less good. If Radio 3 takes its fatal first step down the Classic FM road, that will be because Kenyon and co have finally lost their nerve.

And Radio 4 - blessed or cursed with the most vociferous listeners' lobby in the world - is on the brink of the sort of revolution that often follows change at the top.

Revolution can rejuvenate, but Radio 4 controller James Boyle must beware of basing his on false premises, the chief of which is that he should sacrifice all on the altar of a new, young, street-smart audience. The Guardian polemicist who sneered on Wednesday that "no one listened" to anything on Radio 4 (apart from Today and The Archers) showed sublime contempt for the constituencies of its specialist slots. Most of the channel's drama may indeed be dire, and Kaleidoscope mediocre, but isn't that patchwork of specialised slots Radio 4's real strength?

Yes and no. Listening this past week to the programmes under threat, I set my alarm for an edition of Farming Today. With hurriedly gobbled items about "field-margin set-aside", and "areas of cross-compliance", it put me swiftly back to sleep: no wonder farmers don't tune in. Yesterday in Parliament (under threat) was actually much jollier and sharper than the soporific Today in Parliament (sacrosanct?), which should get the chop instead.

Having missed the scrutiny of dead-celeb coverage on Mediumwave, I was waiting for the repeat when news came through of Vincent Hanna's death. Even without his genial incisiveness, Mediumwave - which, like all magazine slots, is inevitably patchy - should be seen as an essential critical safety-valve. Meanwhile, Does He Take Sugar? investigated the market for motorised wheelchairs, and put the Transport Minister Glenda Jackson on the spot. To axe this eminently useful programme would be an outrage.

The Moral Maze on euthanasia was gentlemanly, gripping, and genuinely illuminating: Boyle is absolutely right to propose shunting it out of its slot. Who has the luxury of an unbroken hour's concentration at nine in the morning? No one who goes out to work; no one with a busy life - children, telephones, tradesmen - at home. The same should hold for Melvyn Bragg's Start the Week: it too should get an evening slot, not a lethal injection of celebs.

The whole point about celebs is that their mental energies are devoted to maintaining their image: they don't have thoughts. Which brings us to another can of worms, viz the internal BBC report which laments the decline in programmes on world events.

The report focuses on television, but it could equally well apply to Radio 4: in the past seven days, there has been precisely one Radio 4 programme about the world beyond our shores - a 15-minute, elegantly scripted trifle called Roxburgh's Russia. Tim Whewell's Return of the Nomad, which was broadcast the previous week, was a reminder of what fascinating stuff one-man-and-a-tape-recorder can produce, if pointed in the right direction: building a yurt, ritually slaughtering a sheep, hanging about on the steppes of Kazakhstan. And if the BBC want further convincing about the riches waiting to be mined, they should swallow their prejudices and listen to the World Service Newshour.

Meanwhile, over in the calm waters of Radio 2, an interesting campaign has been launched: Talking Sleep, accompanied by phone-ins and a helpline. More than 5,000 people called in during the first two days; much good advice on how to combat insomnia was doled out. Personally, I find Today in Parliament works a treat.