Meanwhile, back at Channel 4, enter a new guru...

David Brook will be the mind behind Channel 4's new image, says Paul McCann.

The pace of change at Channel 4 under new chief executive Michael Jackson showed no signs of relenting last week when Jackson poached one of the best-respected thinkers in the media.

David Brook, the man who as marketing director helped move The Guardian from its old Labour, sandal-wearing image to its modern incarnation, starts at Channel 4 today. He has spent the past 21 months at Channel 5 where he is credited with overseeing one of the most successful aspects of the channel's launch - its brand image and market positioning.

There is a feeling in television that, in the past, marketing has not always had the highest priority. "The old monopolies didn't need to worry about competing so they didn't worry about marketing," says Brook. But times have changed.

At Channel 4 he will be in charge of the channel's marketing strategy and the start up of its digital terrestrial art house film channel. C4 already has a good reputation for marketing its programmes and image. This goes beyond poster-hoardings for the occasional drama series and includes the loyalty its viewers feel for the channel as a whole. Yet there have been tensions. Some artists, such as Alan Bleasdale, have been known to change the content of campaigns because they don't think it represents their work accurately - while the marketing department thinks the ad campaigns are supposed to be putting bums on sofas not pandering to auteurs. But Brook is concerned about much more than just the channel's ads. At both The Guardian and Channel 5 he earned a reputation for creating an environment where the overall marketing strategy ran through the whole of the company - like an ideology. Now he and Michael Jackson have to decide what C4's new ideology is to be.

Jackson is known to want to reinvigorate the radical edge of the channel, but Brook thinks it is simplistic just to think in terms of whether the channel becomes more niche or more mass market. Just as Tony Blair believes there is more to politics than left and right, Brook believes there is more to marketing than upmarket and downmarket.

This is proved in TV by the success of BSkyB which, with its movies and sport, does not fit old up- or downmarket positions. Instead Brook categorises C4 viewers as having a constant appetite for change and a willingness to embrace the new. Brook is adamant that his arrival does not herald the advent of television by focus group - rather, the marriage of creative skills on the editorial side with his research and sense of what might work.

"Marketing is anticipating the needs of people and working out how to satisfy them," he says. "It gives you an edge in anticipating what people will accept." It is this thinking that created innovations at The Guardian such as The Guide listings section and the Weekend Magazine. The difference now is that while The Guardian was a niche brand with readers who are rarely tempted to go anywhere else, C4 is attempting to change and stay accessible to millions while taking on more competition than ever before.