The week in radio: Waffling Watts's royal appointment is a real wind-up

It's possible that when the actress Naomi Watts, ensconced in a suite at Claridge's, donned a set of headphones to speak to Radio 5 Live's Simon Mayo for an interview, she had already read the abominable reviews for the film, Diana, that she was supposed to be promoting and thought to herself: "Why bother?" Or it could be that room service had arrived earlier than expected – and given the choice between Simon Mayo and a plate of macaroons, well, it's a tough one even for the most committed self-publicist.

But listening to the interview, which was broadcast on Kermode and Mayo's Film Review in its unedited and curtailed state last Friday, it's still hard to see what prompted her to pull the plug.

Things seemed to get tense when Mayo said that he gathered that, in the course of her research into the late Princess's relationship with the surgeon Hasnat Khan, Watts had spoken to some friends of Diana's, and asked if they were happy to talk. "There are some people I've spoken to that were willing, yes. And I will not name them," came the curt reply.

When Mayo asked whether the crew had permission to film outside Kensington Palace, it was with unmistakable frostiness that she said: "Yes, we had permission", and then, out of the blue, added: "I think we're getting the wind-up. Sorry. We're getting the wind-up." And that, apparently, was that.

If their conversation revealed anything – aside from the crashing boredom of another celeb in dead-eyed promotional mode ("Yeah, Diana was inspirational, yadda yadda yadda", Watts's inner voice was probably screaming. "Where are my bloody macaroons?") – it was the horribly orchestrated nature of the modern celebrity interview. This much was clear through the sotto voce murmurings of Watts's people in the background.

It was similarly clear in Mayo's bewildered plea – "We've been given 10 minutes and we've had eight and a half!"– as if another 90 seconds would suddenly uncover both the essence of Diana and the person playing her. Not that Mayo was to blame for this particular fiasco, but interviews such as these, in which a famous person foregoes regular conversation in favour of PR-approved waffle, benefit no one, least of all the listeners. So why do them at all?

To hear a celebrity interview done right, Jane Garvey's conversation with Fleetwood Mac's Stevie Nicks on Woman's Hour on Monday was a masterclass. It helps, of course, to have a good subject and Nicks is better than most. She used to be known for her diva-ish ways – at the height of her fame she insisted that her hotel rooms be painted pink and furnished with a white piano – but now, at 65, has reached a plateau of wisdom and total coolness.

There was nothing here that was off-limits: her insecurities, her drug addictions, her relationships with bandmates Lindsey Buckingham and Mick Fleetwood. Most fascinatingly, she talked about her first meeting with fellow Mac member Christine McVie. "From the very beginning we made a pact that we would be a force of nature together, and we were," Nicks noted. The pair vowed that they would never stand in a roomful of male musicians and feel any less important. She did this, she said, "with very tall boots... So I wasn't five foot one and a half, I was five foot eight. And so I looked like a tall slender girl that could be carrying a sword."

As an interviewee, Nicks was a gift: a smart woman wise to the promotional process but happy to reflect, debate and analyse – to really, truly talk.

twitter.com/FionaSturges