If all goes to plan, and there is plenty of evidence to doubt that, the British public can look forward to more than 400 new television channels by the end of the year.

The figure will charge some with excitement and fill others with dread. But most people will simply be left scratching their heads and wondering how to make sense of the matter.

Many will find the choice of channels bewildering

Ironically, for a medium which promises pin-sharp picture quality and hi-fi sound, digital television presents a confused image to the public.

The scene has not been helped by a succession of squabbles - some still unresolved - between the various companies with a stake in the digital future.

In about 20 years, all television will be broadcast digitally. Until then analogue and digital output will run side by side to allow viewers plenty of time to make the switch.

Leading the revolution are three rival "platforms":

• ONdigital - formally British Digital Broadcasting, which is led by ITV franchises Granada and Carlton.

• BSkyB - the established satellite broadcaster which is partly owned by Rupert Murdoch.

• CWC - Cable and Wireless Communications, already an established provider of analogue cable television.

All three are racing to be first off the blocks and have pledged to be on-air by the autumn, although none have so far set a specific date.

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But behind the slick marketing facades beginning to emerge from each camp, is a cut-throat fight to attract the all-important viewer numbers.

ONdigital is the only terrestrial broadcaster of the three, and therefore best placed to bring in the biggest audience as viewers will receive pictures using their existing TV aerial.

One of the main selling-points of digital broadcasting is its far greater capacity, and ONdigital plans to launch with 30 channels. About half the output - including the current five terrestrial stations, BBC's 24 hour news channel and a new ITV station - will be free.

Sky is planning up to 200 channels

The rest will be available on subscription and include a handful of Sky channels carrying sport and films.

But, as with BSkyB, viewers will be expected to spend upwards of £200 on a set-top box to decode the digital signals. Although ONdigital says its decoder will work on Sky, the same is not true in reverse.

BSkyB is promising 200 new channels over satellite - viewers can dig deep for a new, smaller dish or reposition their old one. The output will include Sky's raft of movie, news, sport and general channels, as well as BBC stations and Channels 4 and 5.

But, crucially, ITV is refusing to team up with Murdoch after BSkyB was thrown out of the ONdigital bid.

The cable bid

Like CWC, which will carry all the current terrestrial channels, much of the capacity will be devoted to near-video-on-demand. This is where one film is shown on several channels, but with its start time staggered at intervals such as 15 minutes.

The result is that viewers are never more than a quarter-of-an-hour from the beginning of a movie.

Flextech, a pay-TV company with eight channels including Living, Bravo and UK Gold, will go out on all platforms, although ONdigital has initially limited it to just four channels.