Abi Morgan's shocking TV drama Sex Trafficwon awards worldwide. Her new film, about the aftermath of the tsunami, is even more ambitious, writes Gareth McLean

When she was writing Sex Traffic, the brilliant and brutal 2004 drama about two eastern European women forced into prostitution, Abi Morgan noticed a change on her journey home. She took the bus from the railway station to her house in London as usual, but the streets no longer looked the same. She was researching the horrific circumstances in which thousands of trafficked women find themselves - the deceptions, the kidnappings, the rapes, the imprisonment - so when she looked out of the bus window she saw more than just shopfronts and houses.

"I know there are brothels along that road home. I know trafficked girls work there," says Morgan. "There are roads like that everywhere. I really wanted the world to feel what I had felt when I knew that. Good art - anything truthful - should make you look at the world differently." Sex Trafficwon best drama serial at both the Baftas (British Academy awards) and the Royal Television Society, as well as awards from Canada to Monte Carlo. But Morgan was already no stranger to accolades. Murder, her 2002 drama starring Julie Walters as a mother whose son has been brutally murdered, also picked up a number of awards. This was another unflinching exploration of a life blown apart by circumstance. Morgan says she finds herself drawn to these "moments of explosion".

"I'm often trying to make sense of something that's overwhelming. Meeting people on the other side of an experience - a mother who has lost her son very suddenly and very violently, or women who have been trafficked - is something that fascinates me. How do you lose a child and survive? How do you get up in the morning, have breakfast, look out the window?"

But she doesn't just imagine. Murder, like Sex Traffic, was based on extensive research. "I met one mother whose son had been murdered several years before. She was laughing about something. She laughed a couple of extra beats longer than the rest of us would and I suddenly thought, 'Oh my God, you've gone mad.' She had gone to madness but come out the other side. When something so tragic happens, there's a fearlessness that comes from that. The loss of a child reduces everything. At its most profound, the loss of a child isn't just the loss of the present, it's the loss of the future. It's a loss of something of yourself."

Do people ever recover from such loss? "I don't think you ever recover the person you were. I think you perhaps reconcile yourself with the person you've become. I would certainly say, from my experience of the girls I met who had been trafficked, they were still bearing the physical scars obviously, and the mental scars formed part of who they are. I think trying to recover the person you were is impossible."

Now Morgan has turned her formidable imagination to another moment of explosion - the tsunami on December 26, 2004. Specifically, she turns her attention to the aftermath, as a disparate group of people try to cope with the chaos wreaked in Thailand.

Dramatically, the story has much that preoccupies Morgan - a tumultuous event, ramifications that are both personal and global, lives in disarray.

"The attraction of the tsunami is that there's a very simple metaphor - a wave comes in and sweeps people's lives away," she says. It's an ambitious drama with a cast that includes Toni Collette, Tim Roth, Chiwetel Ejiofor, Sophie Okonedo, Hugh Bonneville and Gina McKee. At its heart, again, there is the loss of a child.

Morgan spent 10 days in Thailand researching the project, speaking to hundreds of people, in NGOs and the Thai government. Would she describe Tsunami: The Aftermathas a docudrama? "When I think of docudrama, I think of timelines flashing up on the screen and often more sketchily written characters. Part of the need and the desire to make Tsunami a fiction was that you can't do justice to an individual story. You can't fulfil what someone would want you to, so I told an amalgam of stories.

"But there's nothing in there that isn't based on fact, even the most shocking events." And shocking it is, from the hopelessness of the British diplomats to the landgrabs carried out by foreign hotel groups, eager to build on devastated fishing villages. The pain of a widowed mother trying to get her injured son back to the UK is painted as vividly as a Thai man's grief at the loss, first of his family, and then of his land. As well as wanting to change the way her audience feels about the disaster, Morgan is aware of the responsibility she has.

"You write the emotion, though you've never been there. I have to really trust my gut and write how I think I would respond as a human being, based on the people I've met. With Tsunami, you're writing something that people are still living with, and the least you can do is tell the world about it - so maybe people will come back and say that they are sorry about the loss, that they'll remember the loss in a year's time. Not because they read about it in a newspaper, but because they saw the story on TV and imagined what it must be like to come home to a silent house."

Morgan's facility for emotional truth was honed in theatre. Her father is a director and her mother an actor, but Morgan (38) says she knew as a child that neither profession was for her. Nor was she "one of those kids who wrote from an early age. I was a big liar, though. That went way into my teens. It was like, 'My dad's a policeman. And he's got an Alsatian. And we've got a swimming pool and you wouldn't believe what happened last night . . .'."

In 2002, Morgan won an Olivier award for most promising playwright (for her play, Tender, at the Hampstead theatre), and she has been compared to Caryl Churchill "in her gift for ambiguity and innovation". Her earlier play, Splendour(2000), was about the fall of a totalitarian regime in an unnamed east-European country, with the same events told and retold from multiple perspectives.

Unusually, Morgan is as at home in TV as she is in theatre, although both demand different disciplines. "TV isn't a place of themes but of story, of plot. In theatre, I'd write this long, beautiful poetic monologue and yet the rest of the dialogue would be really lean.

"On television, you can have the fantastic image to replace the monologue. TV's power is that it doesn't wallow in poetry, it keeps driving the story forward."

That said, she is looking forward to writing for theatre again. She has a commission from the Almeida to fulfil next year, before which she is adapting Sebastian Faulks's book Birdsong for the big screen. She has already completed a film script for Monica Ali's Brick Lane, and is working on a piece for Channel 4 about asylum and immigration.

Morgan says she writes to put order in her life. "Chaos is my natural habitat. I write about chaotic situations and about people finding their way through the chaos, the hope that you can find your way. Not to sound too much like Celine Dion, but I have tremendous faith in the human spirit." ( Guardian News & Media)

• The first part ofTsunami - The Aftermath is on BBC2 at 9pm tomorrow