It’s not unusual to see a pop concert on TV where teenage girls and a group of middle-aged men are separated by safety barriers, as the glow sticks wave and the band’s name is excitedly chanted. But in Storyville: Tokyo Girls (BBC4, Tuesday), there was one fairly major twist: the teenage girls were the band, and the middle-aged men their swooning fans.

As this jaw-dropping documentary explained, the girls in question are known in Japan as ‘idols’. Their songs tend to be about how demure and innocent they are; and to prove it, they often perform in school uniforms — although with skirts a lot shorter, I suspect, than is traditional in most Tokyo schools. There are now around 10,000 idols in Japan and the industry is worth $1 billion a year, with the money made not just by live shows and webcasts, but also by meet-and-greet events, where the men queue up (and pay) for the chance to shake the girls’ hands and spend a carefully timed minute talking to them.

Not surprisingly, perhaps, the idols we met seemed a charming if unmistakably business-like bunch. Nineteen-year-old Rio did admit that she initially found the ‘hysteria’ of all those adult men ‘scary’. These days, however, ‘My fans are like my children. I love them all equally.’

As for the smitten blokes themselves, they spoke of their passion with a mixture of pride and something close to hopeless resignation. Fiftysomething Mitacchi told us that his idol worship costs him at least $2,000 a month. (‘I used to visit my parents a few times a week,’ he added. ‘They know why I don’t visit any more.’) Nonetheless, his misty-eyed look as he recalled the thrilling moment at one handshake event when ‘a girl I had a crush on asked my name’ suggested that he considers it money well spent. Obsessive Rio fan Koji, 43, reported that at her 21st birthday concert, the men behind him ‘looked happy and desperate at the same time. It was so moving.’

The programme did attempt a few sociological theories as to why idols have become such a mainstream part of Japanese life. Oddly, though, any possible psychological or — let’s face it — sexual factors were almost entirely overlooked. At the risk of being indelicate, it would, for example, have been illuminating either way to know if any masturbation is involved in the fans’ response. But on this, Tokyo Girls remained rather demure itself.

As we know, this hasn’t been a good month for capitalism in the raw — and on Wednesday it received a further knock from BBC1’s The Week the Landlords Moved In, a new life-swap series in which private landlords stay for a few days in one of the properties they rent out.

The opening episode introduced us to the father and son team of Peter and Marc, who profit by £15,000 a month from their tenants — and who here made the schoolboy error of starting off in bullish form. Having boasted that his dad’s mantra is ‘Let it and forget it’, Marc cheerfully pointed out that, ‘Some people are saving up for their first house. I’ve got 40.’

Even so, he was keen to stress that ‘I pride myself as a good landlord’ — which duly meant that he was in for quite a shock. As the programme had already shown us, the flat he and Peter would be staying in had mould, a broken-down kitchen, freezing bedrooms and a 66-year-old tenant called Linda who works three jobs to pay her monthly rent of £950. She would have complained, she said, except that in the absence of a tenancy agreement she could be kicked out at any time.

Faced with all this, Peter stuck for a while to a pretty stern line, wondering if somebody who couldn’t afford to heat the place should really be living there. Marc, by contrast, experienced a tearful conversion, as he realised — apparently for the first time — that ‘I’m responsible for someone else’s living conditions. I never imagined it would be like this.’

This public confession of his crimes by a sobbing capitalist might make the programme sound faintly Stalinist. In fact, its politics could best be described as Dickensian — in that its proposed solution to the enormous social problems it raised was merely that the individual landlords we happened to meet should behave more kindly.

So it was that, by the end, Marc had refurbished Linda’s flat, drawn up a proper tenancy agreement and offered to help with her electricity bills — which made for an undeniably heart-warming finale. Yet if it crossed anybody’s mind that these improvements may not have happened if Marc and Linda hadn’t been on a TV show (or that other British tenants not on the telly mightn’t be so lucky) they didn’t think to mention it.