Rainbow (ITV, 1972-95)
starring Zippy and George

A ten-year-old of today watching a favourite television programme like Blue Peter, Newsround or Grange Hill might not realise that their mums and dads were watching those same shows when they were children.

Blue Peter, for example, regularly changes presenters every few years to keep the programme fresh and must keep pace with modern production standards and audience expectations. Parents watching today will still recognise a version of the 'Barnacle Bill' theme tune and the famous ship badges, which have been around since 1963. The programmes features follow the long-lasting tradition of exploration for enquiring minds.

Some programmes are less likely to run and run - a one-off serial of just a few episodes is quite different from a soap opera like Grange Hill, which is built to last and has run since 1978. Others, meanwhile, have timeless qualities which mean they will be endlessly repeated. BBC1 ran Bagpuss almost constantly for 13 years despite only one series of 13 episodes ever having been made.

While adult soap Coronation Street has been on air since 1960, most television programmes will not last that long. Programmes on both ITV and BBC have always been under pressure to pick up large audiences fairly quickly. If they don't they will be dropped, never to return. Children's television has been protected from strong ratings pressures since the 1950s and this has given producers the luxury of time to develop and improve programmes. This seems to be changing now and the future may see a more rapid turnover of children's programmes.

While some programmes continue to run year in year out, many old series and characters have been rested then revived years later for new audiences. Andy Pandy and Bill and Ben the Flower Pot Men, both born in the 1950s, have returned via new technology. Basil Brush is now starring in his own sitcom after more than 15 years away from our screens. Such revivals of familiar 'brand names' appeal to nostalgic parents who trust these shows to entertain their children.

These are the Top 10 longest-running children's programmes:

1. THE SOOTY SHOW - there's been the odd change of title but a series featuring the yellow bear has been on television every year since 1954
2. BLUE PETER (first shown 1958 - ongoing)
3. NEWSROUND (1972 - ongoing)
4. JACKANORY (31 years between 1965-96)
5 = CRACKERJACK (29 years 1955-84)
5 = RECORD BREAKERS (29 years 1972-2001)
6. HOW (28 years. First shown 1966; its revival HOW 2 has run since 1990)
7. DOCTOR WHO (26 years from 1963-89)
8. GRANGE HILL (on air since 1978)
9. RAINBOW (24 years in various forms from 1972-96)
10 = PLAY SCHOOL (21 years from 1965-86)
10 = ANIMAL MAGIC (21 years from 1962-83)