One of the defining symbols of childhood is a cat made from rags called Bagpuss. Another is John Noakes on Blue Peter or the oscillating cardboard cut-out figure of Captain Pugwash. For those of a certain age, it is coming home from school on Friday to watch a middle-aged man in a suit and tie encourage what counted for mayhem in those days of panamas and blazers. The young studio audience had to shout out, very loudly, "Crackerjack!"
Children's television in Britain began in 1946 when BBC Television resumed transmission after the Second World War. One of its first successes was the original Muffin the Mule in which the puppet danced on the top of Annette Mills' piano, its feet only occasionally touching the instrument and its strings all too visible.
But even in those early days there was an intention that children's television should be a "service in miniature", offering the full range of programme genres available to adults. The department blossomed, notably with the lunchtime Watch with Mother series that made favourites of such characters as Andy Pandy, the Flowerpot Men and the Woodentops.
The BBC's aversion to American imports and Enid Blyton-type stories also gave the output a certain worthiness which gave the new independent opposition its chance. When ITV began in 1955, its populist touch left the BBC floundering.
One of ITV's first great successes was the film series The Adventures of Robin Hood. Each 26-minute film was made in four and a half days on location near Walton-on-Thames. Sets were made out of stock items. There was a stone flight of steps, an archway, a serf's hut and other components, each mounted on wheels. It is said that the crew could re-marshal these and similar elements into a completely new set in six minutes.
Other filmed adventure series followed: Roger Moore got an early screen break when he was cast as ITV's Ivanhoe. Meanwhile the BBC redeveloped a "toddlers' magazine" called Blue Peter into something very like the present programme - in 1966 it was watched by nearly 60 per cent of all children between the ages of 5 and 15. With this boost, the BBC enjoyed a revival and by the beginning of the 1970s the two networks were competing on more or less equal terms.
This competition resulted in creative, quality programmes which served the young viewer extremely well for 20 years. Gritty new drama series were established such as Grange Hill (1978) and Byker Grove (1989) on the BBC and Press Gang on ITV (1989-1993). Factual series covered natural history, art and books, and entertainment shows spilled out of the after-school slot, with the children's departments occupying Saturday mornings.
Some series became cults with older viewers. In the 1960s, a generation of students made a daily date with The Magic Roundabout, convinced that Dylan the guitar-strumming rabbit was high on cannabis and that the sugar lumps sniffed out by Dougal the dog were not as innocent as they seemed. From an adult standpoint today, it is easy to view such programmes of the past through rose-tinted glasses, be they the Sunday teatime classic drama serials or the first Saturday morning show, Noel Edmonds' Multi-Coloured Swap Shop (1976-81). But what will today's children remember with nostalgia from the present output? And, in these digital days, what dictates what they watch?
The recent arrival of scores of new channels should, in theory, have developed the range of output even further. But though these seemingly non-stop channels have wildly increased the hours of programming on offer, they have also fragmented the audience. What's more, this profusion of choice has narrowed the range of viewing for many children. Since children are expert navigators of the electronic programme guide (EPG), they deftly seek out their preferred genres, notably animation but also soaps and the various digital music channels.
For those who rarely use an EPG, it may be worth noting what is now on offer for young viewers:
* BBC1 carries about 16 hours a week of children's programming, branded as CBBC on weekday afternoons after school and on Saturday mornings.
* BBC2 now shows around 24 hours a week, mainly on Sunday and weekday mornings, much of it consisting of repeats from the BBC's children's digital channels, and it is branded either as CBBC or (for pre-school children) as CBeebies.
* ITV's output for children is being squeezed, and is now limited to 10 hours a week, on Saturday mornings and in the post-school weekday slot, which is cut off at 5pm to make way for more lucrative adult programming.
* GMTV is a separate company providing the breakfast sequence on the third channel. It is 25 per cent owned by Disney and carries about five hours of children's shows a week, all provided by Disney.
* Channel 4 is unique in that it has no legal obligation to show out-of-school programmes for children but nevertheless transmits some early morning shows and a Sunday morning sequence (mainly consisting of repeats) aimed at teenagers and labelled T4.
* The network providing most hours is, perhaps surprisingly, five, once known as Channel 5 (see box).
But while these terrestrial channels are still regarded by many adults as the "main" channels, recent audience figures indicate that nearly three out of four children have access to digital television delivered either by cable, satellite or Freeview. And those with this option spend 80 per cent of their viewing time tuned to digital channels.
Pre-eminent among these are the two BBC children's channels, CBBC and CBeebies. When the BBC management was asked if it was not confusing to give them the same names as the output on BBC1 and 2, it pointed to in-house research which indicated "the labelling is perfectly well understood by its target audience". CBBC targets 6 to 12-year-olds; its publicity people describe it as "rocket fuel for kids" and it transmits for 12 hours a day.
These include four hours of schools programmes, broadcast daily during term time. A quarter of its output is new programming, half consists of repeats and the remaining quarter is "acquired" - that is, bought in from other sources, including the US. CBeebies is the pre-school channel, broadcasting a four-hour block of programmes three times a day followed by a "bedtime hour" at 6pm. Given all this, it is not surprising to note that only 5 per cent of its output is a first-time showing.
Most of the other channels rely heavily on cartoons, such as Boomerang, the Cartoon Network, Toonami and the Nickelodeon family of four networks which includes Nick Toons (cartoons) and Nick Junior (cartoons). Disney also offers four channels though without adverts (that is, provided you ignore the associated Disney merchandising). Some "youth" channels are a little different. Discovery Kids offers some factual programming. Trouble is targeted at young teenagers - one of its current lead shows is an American soap called The Sausage Factory. Among the main characters are (to quote Trouble's website) JC, the "original skate and surf dude". He appeals to "more mature ladies who think he could be a sort between the sheets". Then there's "uptight Lisa" and the clean-cut hunk, Posh Ted. Sadly, money doesn't buy him happiness (or, more accurately, sex) because girlfriend Nancy "won't put out".
Last month, BAFTA (the British Association for Film and Television Arts) staged a debate about the real crisis facing children's television. Among the questions posed were whether children need to be fed a varied media diet as much as they need to be protected from junk food, and whether commercial pressures (plus freer regulation) will result in fewer quality home-grown programmes and more imported ones.
The answers are to do with money. Thanks to its expansion, television is no longer the affluent industry it once was. From the advertisers' point of view (and it is they who fund most channels), it is unfortunate that their rapid proliferation has not been met by an equal expansion of the population. Roughly the same number of young viewers are watching 20 channels as once watched two, so revenue falls. ITV has been worst hit.
Meanwhile across on BBC1, Blue Peter will never again achieve a 60 per cent reach.
One result has been the internationalisation of the market. Programmes must now earn income from overseas sales, and some are modified for this purpose. But, inevitably, creating programmes for world-wide markets can result in blandness. As Jocelyn Hay of the pressure group Voice of the Listener and Viewer, observed: "The best programmes aren't exportable."
Two other related issues surfaced during that debate. One was the murky area of product placement. "Paid-for" references (visual or verbal) are prohibited on British television. Nevertheless, McDonald's and Coca-Cola often feature in desirable ways in American imports. The attitude of the regulators seems to be "you just can't stop it".
The other issue is the prevalence of cartoons and other forms of animation.
Parents, even those who grew up on a diet of Tom and Jerry, as well as politicians and teachers, may lament the profusion available, but children can simply vote with their handsets.
Oliver Postgate, the man who animated Bagpuss, Ivor the Engine and The Clangers, has developed a doomladen argument in an essay posted on the net.
"Today, making films for children's television has become very big business requiring huge capital investment," he says. Consequently executives insist the format of each production must suit "the largest and dumbest market", which means making more of what is already known to attract "consumers". So out goes originality, and style triumphs over content.
Almost every channel has its own website, which can be found by searching the channel name or other key word.
* Mammoth website of the regulator Ofcom: www.ofcom.org.uk
(For its 2004 Consultation on Children's Television, search "7.2.2 Children's".)
* Voice of the Viewer and Listener www.vlv.org.uk
* Oliver Postgate: www.oliverpostgate.co.uk
* The BBC Governors' Annual Report: www.bbcgovernors.co.ukannreport
* Media UK provides details of (and links to) every radio and television station in the country www.mediauk.com
Not all presenters get to skin a rabbit or to dress up as Henry VIII, especially if they are women. Those are just two of the jolly escapades that Fran Beauman and Ania Dykczak embark on in their new series Discovering History. They consult "Ben the Book Reader" for factual information and explain how Tudor ladies blackened their teeth to simulate decay: that meant they could afford sugar. It may occasionally be a bit "girlie" but it succeeds triumphantly in its aim of "making history fun".
It is also typical of several low-budget, imaginative series on what was originally called Channel 5. Launched in 1997, it had some trouble carving a niche for itself between the other commercial, terrestrial networks.
Fewer public service obligations were placed on it than on ITV and Channel 4 and it tried several formats - going downmarket with shock reality programming and soft porn. But it has recently been re-branded as "five", and now offers a range of intelligent documentaries, wildlife and arts programmes, as well as some impressive output for children in its pre-school Milkshake and (for older children) Shake strands each morning.
Shake reflects the new image of five: it offers a wide range of documentaries for young viewers, a genre neglected by other children's departments
Indeed, while the regulator Ofcom requires five to provide 11.5 hours for children per week, it transmits no fewer than28 hours. Its controller of children's programmes, Nick Wilson, denies this is because they are a comparatively cheap way of filling the schedule. "At first, I was told, 'Do as much for as little as possible'." His programmes are still made for a fraction of BBC budgets but the result is often the beguiling informality apparent in Discovering History.
Part of his success lay in his early discovery of a gap in the market for programmes for young children in the mornings. Other channels have since muscled in but, as well as young viewers, Wilson's slots won five a strong housewife audience. The result is that Milkshake attracts audiences comparable to that of the channel's mainstream output, which even makes it attractive to advertisers.