Three programmes spring to mind that have entertained a generation who are now parents and whose own children are now watching: Blue Peter, Grange Hill, and Record Breakers (BBC 1), the 23rd series of which began yesterday with a wonderful memorial to its late presenter, Roy Castle. The same afternoon Get Your Own Back (BBC 1), from a newer, brasher school of children's entertainment whose sole aim is to dunk some innocent into a pool of gunk, returned for a fourth series.
The thing that still strikes you about Record Breakers is its eternal youth. Castle was into his sixties in his last series but he still possessed a boyishness that wasn't remotely artificial: Peter Pan meets the Pied Piper. Thus, though he suffered from vertigo, he broke several records that involved doing daft things at a great height - flying down a rope from the top of Blackpool Tower, wing- walking from London to Paris, paragliding under nine London bridges.
The daredevilishness he shared with John Noakes was combined with an all- round talent in the old-fashioned showbiz disciplines - tap-dancing, multi-instrumentalism, songwriting. There's no way that tap and trumpeting would get you a job for life in TV any more, and probably not even an interview. Castle belonged to a generation of presenters who brought an extra soupcon to the job, rather like the older generation of MPs, because he had been around the block before he got on the box. Nowadays, all you need is a dayglo personality, a matching pair of trousers and an ability to stand next to a pool of gunk.
The source of Record Breakers' longevity was its ability never to repeat itself. The strange records that Castle either participated in or played host to were the product of a short-trousered imagination - the biggest domino effect, the tallest champagne flute fountain, the biggest tap troupe or jazz band, the largest number of plates spinning on top of bamboo poles. These were the sort of stunts that defied the shifting fashions in children's entertainment.
The problem with a format like Get Your Own Back, in which children bearing a grudge against their adult team partner compete to land said adult in said gunk, is that all it can do is repeat itself. Someone called Dave Benson Phillips, he of the dayglo personality and matching trousers, assured us that some of the set (a cross between a car wash, a dry laundry press and a sewage tunnel) is new. But rearranging the furniture doesn't always alter the room.
One of the immutable laws of children's game shows, apart from the ones that say there shalt be a pool of gunk and much ear-splitting, high-pitched screaming in the audience, is that one team shall be dressed in red, the other in yellow. No change here, but the twist is that the two teams compete internally as well as with one another. Each young contestant wants to keep their partner's score down, while the adults compete with each other to avoid the gunk dunk. It's quite complicated, actually. But it won't run to 23 series.