Keeping audiences on the edge of their seats: It's all in the script

As the co-creator of cult thriller 24 - series six is now in production - Bob Cochran knows what is needed to keep audiences on the edge their seats. He discusses techniques with Ciar Byrne

In Britain we like our television scriptwriters to be lovably eccentric - think the anarchic Paul Abbott, the flamboyant Russell T Davies or the wonderfully indiscreet Andrew Davies.

In the US, TV dramatists are a more serious breed altogether. Bob Cochran, co-creator of the cult thriller 24, could be a character in his own slick drama: one of the senators routinely threatened with assassination until federal agent Jack Bauer, played by Kiefer Sutherland, saves the day.

A larger-than-life figure with a mane of silver hair, Cochran is on a tour of duty in the UK, where he has been invited by the MediaXchange to talk to British drama writers and producers about how to create and sustain successful long-running series. He should know. The fifth season of 24 has just concluded on Fox in the US and is still showing on Sky One in Britain, while work is already under way on series six.

"I think we just hit upon a happy combination of elements. There was nothing on air like it," Cochran explains. "The fact it was different helped and the fact we were about to create a consistent atmosphere of tension and keep that edge-of-your-seat feeling up over time.

"Kiefer Sutherland was huge, because he inhabited the character of Jack Bauer, made him real and fascinating to watch and embodied all the tensions and the contradictions, the edginess of the show."

Downloads of 24 have just been made available on MySpace.com - which like Fox is owned by Rupert Murdoch's News Corp - and in the UK, Sky is showing each episode of the drama with five different start times to accommodate the World Cup.

Despite being an executive producer on the show, Cochran is blissfully unaware of these technological advances. He is a scriptwriter of the old school whose sole concern is whether or not a story works on screen.

Cochran's early years were spent on the move. His father was in the navy, and the family did not settle - Monterey, California, until Cochran was 12. After attending Stanford Law School, he briefly practised law in San Diego, before studying for an MBA at Harvard and working for the consulting firm McKinsey. But while he was pursuing careers in business and the law, he harboured a secret desire to write for television. After finishing several scripts, he finally submitted one that caught the attention of the team at LA Law.

It is an unconventional route into writing for television, but Cochran believes any experience can feed the imagination of a scriptwriter. "The material all writers work with is human nature. If you're observant and watch the way people think and act and react and you're honest about your own feelings, I think you have enough material to be a writer, no matter what your background," he says.

From freelancing on LA Law, he secured a job on the final season of prime-time soap opera Falcon Crest, a companion show to Dallas, where he met Joel Surnow. Stints on Sons and Daughters and cop show The Commish followed, before Cochran and Surnow teamed up again on La Femme Nikita.

The television series based on the film of the same name gave the pair an appetite for the thriller, which resurfaced when Surnow contacted Cochran with an idea for a new show.

Cochran was writing historical mini-series, a personal passion, when he took Surnow's call. "He had this notion for 24, just the framework. He said, '24 hours, 24 episodes, each episode is one hour of the day.' I said, 'What's the genre, who are the characters, what are the stories? He said, 'I don't know.'"

When they sat down together to put flesh on these bones, they addressed the question of what situation would keep the hero awake for 24 hours.

"It felt like it had to be some sort of thriller, like the original The Day of the Jackal with Edward Fox and Clint Eastwood's In the Line of Fire, movies that had a real tension and an end point that everything converged on - the assassination attempt," says Cochran.

The next issue was how to create a personal story line for Bauer. "The problem was that in a 24-hour period there's no personal crisis that you can't put aside, even if you're getting divorced, or you're diagnosed with an illness. We came up with the notion of what if your teenage daughter ran away from home. That would certainly get your attention."

So the first season of 24 was born, in which Bauer, an operative with a fictional Los Angeles-based counter-terrorism unit, copes with an assassination attempt on a presidential candidate and a missing teenage daughter, placing extra strain on a marriage already damaged by an affair with a colleague.

The ground-breaking format threw up immediate technical difficulties, notably the impossibility of time cuts. "We have to account for every single second of every hour of this day. Most television shows and movies, if you put a guy on a plane to Los Angeles to fly up to New York, you can cut to New York and he's there. On our show, he's on the plane for five episodes," explains Cochran.

To compensate, the scriptwriting team came up with several different intertwined story threads - following the hero, the bad guy, the target of the assassination and the hero's wife and daughter. They employed the device of a split screen, which has become synonymous with 24, inspired by characters in the dramas using cell phones to keep in touch.

Fox originally commissioned just 12 episodes of the show. Cochran and Surnow and their team did not learn until halfway through this initial period that the run was to be doubled.

At the end of the first season, they considered changing the format so that 24 hours passed in each hour-long episode. Cochran recalls, "We actually sat down and wrote a script reflecting that change in premise. It was just disappointing to us. We felt that's not the show. There's nothing special about it, nothing different. It doesn't have the pace, the drive that the first season came up with, so we decided to bite the bullet and keep the format and of course it has worked out."

24 was devised before the terrorist attacks of 11 September 2001, but aired shortly after. At first, Fox and the writers questioned whether it was appropriate to proceed with the show, but their decision to go ahead has been vindicated. "If things are as terrifying or disturbing as terrorism certainly is, people want to try to make sense out of it and one of the ways you do that is by telling or watching stories about it," says Cochran. "Second World War movies were made and people went to them while the real war was being fought in the world."

The writers incorporate terrorists from across the globe to avoid repetition, but Cochran insists 24 does not have a political stance. "We've been accused of being left-wing because the bad guys have corporate oil interests, and we've been accused of being conservatives because we seem to be pro-military and there's so much torture on our show."

If 24 is formulaic, it is a formula that is working. The fifth season enjoyed higher ratings in the US than the previous series. Cochran insists, "I would like to leave before our welcome is worn out." But that time is not yet in sight.