Is age really nothing but a number?

This three-parter, showing on consecutive nights, takes a sextet of 70- and 80-somethings -- newscaster Kenneth Kendall (86), former tabloid editor and broadcaster Derek Jameson (80), entertainer Lionel Blair (76), ex-cricket umpire Dickie Bird (77), and actresses Liz Smith (88) and Sylvia Sims (76) -- and puts them together in a country house decorated and furnished as if it were 1975.

But there's more to the thing than just vomit-coloured wallpaper and shagpile carpets -- although there's no shortage of either.

The six are encouraged to talk and behave as if it really IS 1975. The hope is that jolting them back to a time when they were at their happiest and most productive will make them feel and act younger.

Daft and gimmicky as all this sounds, it's been done before -- and apparently it works. Thirty years ago, Professor Ellen Langer, who's overseeing The Young Ones with science presenter Dr Michael Mosley, conducted a similar experiment with elderly men at Harvard University.

Process

By the end, the volunteers' physical and cognitive faculties had greatly improved, which suggests that a significant element of the ageing process is all in the mind.

In a deliberate attempt to make our aged celebrity guinea pigs seize back their independence, all of them except Liz Smith (The Royle Family's indomitable Nana), who has to use two walking sticks to get around and is confined to the ground floor, had to carry their bags upstairs.

Watching a huffing, puffing Derek Jameson grumble his way agonisingly slowly up 14 stairs, Dr Mosley, observing on a TV screen, struggled to suppress the natural urge to run and help the man.

"You can help someone to death," snapped a stern Professor Langer.

But once the celebs finally reached their bedrooms, which have been decked out, in as far as possible, to replicate the ones they slept in in '75, the mood picked up.

Kenneth Kendall, who walks slowly and with a slight stoop, glowed with delighted recognition and actually seemed to straighten up.

"Look at him," marvelled Professor Langer, "that's the tallest he's stood all day."

The early stage of the experiment seems to be yielding results. Dickie Bird, who lives on his own in an isolated farmhouse and cuts a melancholy, sedentary figure, is worried that his memory is failing. Tests conducted by Mosley, however, showed Dickie's memory is far from as bad as he thinks.

To prove it to him, he had him memorise the prizes on the conveyor belt in an old episode of The Generation Game. To Dickie's amazement, he remembered most of them.

Not everyone is taking to the experiment so enthusiastically.

"I've never felt younger," beamed Lionel Blair, who, to be fair, looks in good nick for a man of 76. The other five, he said, feel their age. "I don't. It's a terrible thing to say, but I like being among the young."

Lionel's wife, however, feels he's "in denial". The preliminary physical tests suggested he might be. Despite his dancer's body, Lionel's flexibility and lung function are not as good as some of the others'.

"He's the most striking case of someone who thinks he's younger than he is," said Dr Mosley.

It's strange, not to mention a little sad, to see people you grew up watching on television again, when you haven't seen them in years. You somehow expect them to be preserved in amber.

The Young Ones is intriguing and entertaining -- yet it's also a surprisingly poignant and touching look at the harsh realities of old age.

STACEY'S STARS

The Young Ones ****