CABLE television is often regarded as satellite by other means, but local networks are increasingly developing characters of their own. There are currently 58 active cable television franchises in the UK, with more than 450,000 subscribers. The number of franchises is 130, with new operations coming on stream all the time.

Cable networks typically carry the four terrestrial channels and BSkyB. In addition, nationally, there are channels devoted to children's programmes and parliamentary coverage, the latter provided by a consortium of seven cable operators.

But the real impact of cable promises to be in its ability to focus on local or regional topics for specific viewers. Terrestrial television broadcasts regional news, current affairs and occasionally documentary programmes, but the diversity of a regional viewing audience has always made the composition of such programmes a difficult editorial balancing act. Cable operators argue that they can be more accurate in targeting.

The Cable Television Association spokesman, Niall Hickey, points out: 'Cable television companies aren't programme makers - they are a conduit.' But he adds that the companies are increasingly taking the initiative to stimulate local and community programming. Windsor and Birmingham Cable have both appointed managers to look after local origination. Earlier this year, the Association itself set up a local programming group, under the chairmanship of East Lancashire Cable's managing director Ed Madden, to co-ordinate the activities of cable companies.

It is a provision of the licensing arrangements that cable companies produce local output, but the nature and volume of the output has never been defined. The starting point has usually been a form of Teletext service, with visual improvements. Some franchises have developed this idea into a community service. The Watford operator, for example, has formed associations with the police to broadcast details of stolen property.

Individual franchises have taken the idea further still. Croydon has perhaps the longest-established local programming in the UK, with a channel devoted to local news, sports and community events. Cable London has a committee composed of local volunteers who vet programme suggestions from would-be contributors, and decide whether programmes are fit to be screened.

Cable also claims to be the ideal medium for ethnic broadcasting. Cable London has the Hellenic channel and Asian television is available on two of Comcast's three networks.

Local programming is gradually being followed by local advertising. Birmingham Cable led the way in March. 'The reaction of the market was extremely good,' says Comcast International's president Dick Davis.

The 22 London franchises will follow with a fibre-optic network by which they will insert local advertising into, say, Sky advertising breaks.

Part of the appeal of cable as an advertising vehicle is the precision implied by special-interest channels. But its main argument is the ability of the operators to say who is watching what at any given moment. 'I'd say there is growing confidence in cable as a business,' says Mr Davis. 'You will see continuing growth.'