My heart sank like a stone to the bottom of a well when first I saw what was on the radio this week. I think of Radio 4 as a last, pristine refuge for people on the run from voyeurism and emotional incontinence - for those of us who despise reality TV, and don't give a damn how cross this makes our friends when we meet them for dinner (this, for the record, is very cross indeed). But there it was, in black and white: details of a new series called The Real World (Tuesdays, 9.30am), in which members of enclosed religious orders return to "the frenetic pace of life in the 21st century" and keep an audio diary recording their responses to it. It sounded exactly like The Convent, the current BBC2 series for which four volunteers spent 40 days and nights at the Convent of the Poor Clares in Arundel, Sussex - only in reverse.

For some reason, I listened to it anyway. This turned out to be a good thing. In a world that is fast losing its head, The Real World attempts to sound a rare note of moral clarity, and I urge you to try it. After all, it only lasts a quarter of an hour. In part one, Sister Yolanda, from another group of Poor Clares, left her convent to visit a housing estate in Huyton, Liverpool. If I tell you that Sister Yolanda had not set foot outside her enclosure for ten years, except to pay a visit to the dentist, you will understand that this little excursion really was more than a stunt - and, touchingly, you could hear it in the voices of the other sisters as they bade her goodbye at the gate. They twittered like blackbirds who had just caught sight of a greedy-looking tom-cat.

Huyton is famed for being the birthplace of Steven Gerrard, which means that people think of it as poor but striving and decent. In truth, as the residents of some of its wilder estates readily admit, it is often hard to find such decency: the social problems are severe, and drug-related crime is endemic.

But Sister Yolanda was not to be put off. From her car, she observed that she could see a lot of spiked fences and barbed wire. It seemed that she had simply moved from one enclosure to another. Greeted by a church worker who duly informed her - a little too enthusiastically, in my opinion - that a drive-by shooting had taken place, she simply said: "Well, we sang 'We Are Heralds of Your Peace' this morning."

In Huyton, she spent time with Sue, a foster parent to James, child of a drug addict. Sue and Sister Yolanda did not put the world to rights (the programme was too subtle for that), but they did talk. Their conversation made me cry.

How can I explain it? It wasn't their words, which were banal. It was more that, despite the absence of any posturing or showy piety, each saw the simple goodness in the other, and this recognition worked as balm and encouragement. "She's a nice person," said Sue as the nun left. She sounded relieved that such a thing should exist. For her part, Sister Yolanda observed that Sue was trying to provide James with a life in which he need not live in fear. She understood this: convent life is lived entirely without fear.

Ordinarily, I might have harrumphed at such a statement of the obvious, or accused her of chickening out of the real world. But in a week when, for reasons I cannot go into here, I have been more than usually aware of casual violence, her qualification - "fear stops you from becoming a whole person"

- made perfect sense to me, as it did to Sue.

Pick of the week

Shake It Baby: a history of burlesque
27 June, 11.30am, Radio 4
The presenter Libby Purves will don nipple tassles – over her cardigan.

Worricker on Sunday
25 June, 10am, 5 Live
Investigates the rise in extreme anti-abortion activity in the UK.

Don't miss . . .

Gilberto Gil spearheaded the Tropicália movement in the 1960s, and he comes to the Barbican hot on the heels of a recent themed season. As Brazil's minister for culture, Gil is living proof of Tropicália's influence.

At the time, the authorities saw the movement as a threat, and in 1968 Gil and other musicians were jailed for "anti-government activities". "They gave lots of ridiculous reasons for putting us in jail," he has said. "The real reason was: you are too enigmatic and we can't understand you." Evidence that times have changed.

Gilberto Gil e Grupo play the Barbican on 26 June. Ticket details on: www.barbican.org.uk