PETER YORK ON ADS: ADVERTISING constantly pretends to be other things, particularly the editorial that surrounds it (thus those ambiguous pages in glossy mags which bear a modest disclaimer saying "promotion"). But it is a quite exceptional mark of the modern world when advertising actually becomes programming.

The Miller Pilsner commercial Miller Time fulfils all the key criteria of a real programme: it appears weekly, in a regular slot; it changes from week to week; it has an audience; it has recognisable "strands" and artistes within the show; and it is promoted in its own right as an entertainment on posters and in short "trailers".

The fact that this mini show occupies only a three-minute slot (although it has that break to itself), and that it generates constant reference to Miller Pilsner seems hardly to matter. It is the nearest to a US "sponsored" show that UK advertising has had. It is the more credible in that it has been carefully calculated for its medium - Channel 4 (observers have been known to call it the "lager channel" because of its programming mix). A David Letterman pastiche - for this is the format - is exactly the sort of thing Michael Grade's editors might be expected to buy.

The Letterman figure is called Johnny Miller, and the show appears "Live from New York" with an equally live audience. Starting with the host admitting to being "as nervous as a poodle in a Peking steakhouse", the whole thing has the texture and production values of a real show (unlike, say, the NHS Lotto ad). There's an Elastic Massage person, a star - Alice Cooper, looking his most ghastly and admitting to an obsession with coat hangers - a featured musical director and the whole tool-kit of a Letterman-type programme. And of course it has its obligatory on-screen disclaimer - "This is an advertisement", and later, "This is still an advertisement" - but presented in a way that compounds the ambiguity. It will be widely copied.

! Video supplied by Tellex Commercials.