Last night's viewing - 56 Up, ITV1; Chatsworth, BBC1

Tom Sutcliffe

If you didn't shed at least one or two tears during 56 Up then you might want to check your pulse. It is, by some stretch, among the most affecting television programmes ever made, even when – as with last night's opening episode – it begins in determinedly upbeat style.

Then again, perhaps this is only true if you've reached the age when checking your pulse is starting to seem like a good idea anyway. Watching last night's film with your life ahead of you – as a 21-year-old, say – you might understandably feel that it isn't really about you. That's one of the pleasures of youth, after all, that at some level you think yourself exempt from the gravity of age. But if you've grown up with these characters over the series' nearly 50-year run you will know all too well how steadily the years can reel you in. As Neil, one of the series' more troubled contributors, put it: "No formal education can prepare you for life. Only life can prepare you for what comes."

It wasn't all melancholy. In fact, the first two updates seemed to offer evidence that your fifties can be a kind of ripening of good fortune. Sue, who was married at 24, beginning to regret it at 28 and divorced by 35, clearly had the sense that she'd passed through her hardest times, when she'd been a single mother. The partner who'd appeared for the first time in 42 Up is still with her and her job, as a co-ordinator at a London university, gives her pleasure every day. Paul, one of the most uncertain contributors as a child (he was first discovered growing up in care), appeared to have reconciled himself to a life that still wasn't without anxiety but which was more complete than you would have dared predict from his earlier appearances.

If there is a problem with the series now, though, it's that the accretion of past history has made it increasingly difficult to get a deeper sense of how these people feel. As seven-year-olds, they appeared to share everything, unaffectedly open about their expectations and dislikes, and there is no earlier self to disappoint or disavow. As the years passed, though, some found the cost of candour so high that they pulled out. After 28 Up, Peter declined to be filmed because his disillusioned remarks about teaching had provoked criticism in the media. He was only back now, he explained, because "I feel a lot happier with myself", and because he wanted to promote his band.

Others questioned just how candid they could ever have been. "It's not for this programme to expose my private feelings," said Neil, always the most touching of those involved because of the gap between his childhood self and the hunched homeless young man he became. Now a lay reader and Lib Dem councillor in a Cumbrian village, he's found a place to live but still doesn't seem entirely settled. There's a thread of bitterness and anger in him still, at least some of which is directed at the fact that strangers like me will assume that they understand the particularity of what he's feeling. I probably don't. But he may have underestimated how common it is to feel a sharp pain when you twist your head to look back – the ache that gives this series its force.

They were doing the spring cleaning in the first of Chatsworth, a new series about the Duke of Devonshire's little place in the country. They have some help, including 20 cleaners, a clutch of textile specialists and 21 gardeners. But then, since members of the public tramp through their house for over half the year, they need it. "Tramp" can be the operative verb. Investigating a malfunctioning cistern in one of the public lavatories, one member of staff discovered the explanation – a fouled pair of underpants that somebody hadn't wanted to take home with them.