ALL good institutions create myths; and all great institutions devote energy, sooner or later, to undercutting them. The BBC At War (BBC2, Sunday) told a different story from the one that I had assumed was the case. For most of the Second World War, the BBC (radio, of course, not television) was not the glue that united our nation in its determination to win through: it was popularly considered remote and superior. Politicians distrusted it, and the military thought it was a threat to security.

Slowly and painfully, this perception changed. Some far-sighted commanders realised the public value of eyewitness-reporting from the field of conflict; and Downing Street began to appreciate that independent broadcasting was exactly what we were fighting for.

The troops from the United States massing in Britain thought the BBC so boring that their own network, brasher and more populist, was set up; to Auntie's dismay, millions of British people chose to tune in to it, too.

So, Reithian highbrow censoriousness gave way to more accessible schedules. Along with the advance through Italy, and the Normandy landings, a trained corps of reporters sent back dispatch after dispatch, galvanising support for the troops; and Richard Dimbleby's account of the liberation of Belsen finally revealed the depth of Nazi evil. Studio managers thought the report so harrowing that it could not be broadcast; but Dimbleby said that, if it wasn't, he would never file again.

The audience was far wider than domestic: eventually, 43 languages were broadcast, and 35 million people in occupied Europe listened in (to their great peril) to what was accepted as the one source of truth.

Presented by Jonathan Dimbleby, the programme (the second of two) had extraordinary personal as well as national resonance; at this time of agonising over our relationship with Europe, the significance is highly topical. For those of us committed to another great national institution, the problem of how to develop and change while holding on to core values could not be closer to home.

The yak-herders of the Gobi probably do not tune in to the BBC much on their solar-powered TVs; but, in Kate Humble: Living with nomads (BBC2, Friday), they seem otherwise to have developed a striking accommodation between their ancient way of life and the modern world. Humble is terrific, joining in everything with wide-eyed, girlish enthusiasm, and with the right combination of personal engagement without pretending that she is really one of them.

La Traviata: Love, death, and divas (BBC2, Saturday) was not as good as it should have been. Verdi's revolutionary opera about the realities of contemporary life caused great scandal at its London première in 1856: the papers were appalled by the moral degeneration of a work whose heroine is a prostitute. But Amanda Vickery and Tom Service undermined their exposé of 19th-century hypocrisy with silly presentation, and by focusing on Violetta rather than Germont père, whose transformation from being the embodiment of society's norms is by far the most radical aspect of the piece.