How did 'Lost' lose the plot?

PresentTense/Shane Hegarty:This week's episode of Lost ended with one of its better twists in some time. Good thing too, because the drama's grip is perceptively weakening. It used to keep the viewer hooked on a slow drip of information and revelation, but this third season is irritating for how obviously and clumsily it withholds answers.

It's proven too much for many viewers in the US. When Lost moved to a later timeslot, four million viewers decided not to follow.

It now has eight million viewers less than it had two seasons ago. Its creator,

JJ Abrams, once said that he had enough stories to stretch the show over eight years. If it lasts that long, it may have more plotlines than viewers.

Lost has been compared to The X-Files, another drama with supernatural twists, dark paranoia, mystery, complicated story arc and really hot actors.

It ruled late-1990s TV while keeping cultural commentators busy. A sleeper success, its ratings eventually collapsed under increasingly ridiculous plots, lack of answers and a wounding change of timeslot. It was ultimately done in by the flip of a calendar page. After 2000, the pre-millennial zeitgeist that had carried the show evaporated overnight. Now, The X-Files can be found decomposing on the Sci Fi channel. The earliest episodes were made only 14 years ago, but it looks old.

On Sunday nights, Lost shares a double bill with 24. Jack Bauer's continuing adventures (this is "day six") rely on disposability. Relentless in its search for the next adrenaline shot, 24 churns through plots, characters, schemes and scenes. Paradoxically, it's the secret to its longevity. You do not need to have seen the previous series, or even the previous episode, to join the next.

As with Lost, a lot has been written about 24. Like nothing else, it has reflected and exaggerated the concerns of America at war. It features corrupt presidents, scheming vice-presidents, Muslim terrorists behind white picket fences, the constant threat of attack, and the need to do whatever is necessary to stop all of the above. This week, Jack Bauer cut off someone's little finger using a cigar snipper. It was one of the lighter moments of this series.

Yet, because it is so rooted in the "now" and contains this in-built obsolescence, 24 is destined to fall off the cultural radar as quickly as a finger that's been mistaken for a Cohiba.

Look through the history of television and you'll find plenty of dramas that, in their time, were considered to be ground-breaking, brilliant and unmissable. Many were. But few have been long-lasting.

Writing about the forthcoming movie version of the His Dark Materials trilogy, author Philip Pullman recently observed that "from a storytelling point of view, the novel and the film aren't so different . . . because in both the novel and the film you can use that great narrative device, the close-up . . . " He could equally have been talking about television. But whereas the novel offers opportunities for the reader to play out a close-up against the backdrop of their own imagination, television can't avoid having to show the wider shot. Anchored by fashion and landscape and look, from the moment it is broadcast a TV drama is already sliding out of time. Movies have this problem too, but when compressed into two hours - rather than stretched over 80 - it not only seems less of a burden but often enhances the experience.

Plus, a movie gets its story over with quickly. Television takes years. Even in the age of the DVD box set, it takes real commitment to sit down and watch an old series over again, especially when the great many plot twists may have been shorn of surprise.

Comedy is an exception. Sitcoms flourish through short episodes, great jokes and characters whose inadequacies and frustrations could place them in any period of time. Channel 4's recent list of the Greatest 50 TV Dramas compared unfavourably to a previous list of greatest sitcoms. The funny stuff gets prime-time repeats; you'd be hard-pressed to find the serious stuff anywhere but on a list of great dramas.

Number one, unsurprisingly, was The Sopranos (the latest series also just happened to be starting on Channel 4 that week). But already, the "greatest drama of all time" has competition, because it is currently mandatory for HBO's The Wire to be described as the "best drama on television". It reminds me of a Mad magazine cartoon which showed a street of pizza parlours, the first boasting the "best pizza in the city", the next proclaiming the "best pizza in the country", and its neighbour announcing the "best pizza in the world". And the last pizza parlour? Its sign read: "The best pizza on the block."

Filming has begun on the concluding episodes of The Sopranos. As it goes to the great DVD library in the sky it will be interesting to see if this drama - loaded with undoubted greatness, layered with meaning, and often described as novelistic in scope - will follow the trend or set a new one. It may prove timeless; as much of a classic to the next generation as it is to this one. But it's just as likely to become more talked about than it ever is seen.