BRYONY Lavery has more than 70 plays to her name, but she has never written anything quite like the tender but cruel Stockholm, her first commission for the physical theatre company Frantic Assembly.

"They contacted me? I'd heard about them but never seen their work, so I met the directors Scott Graham and Steven Hoggett.

"I'd been thinking I was too busy, but I liked them so much I just said yes and then went away and said, 'Why did I say yes?', " says the Yorkshire-born playwright, whose play will run at the West Yorkshire Playhouse, Leeds, from Tuesday to Saturday.

"I saw their production of Mark Ravenhill's Pool (No Water) at the Lyric, Hammersmith, which they did last summer, when all they had for Stockholm at that point was the title of the play and the definition of Stockholm Syndrome, and that's all I started off with."

Put succinctly, Stockholm Syndrome is the condition where a captive develops warm feelings towards the captor.

So away you go, Bryony, start writing an unconventional love story exploring the dark side of romance in Stockholm, a city that remains dark all day in the winter months.

"The page stayed blank for a long time, " she recalls.

"The company was doing workshops with two actors and two dancers and I was thinking, 'I don't need to write anything here as their physical language is so eloquent', but then I sat down and I knew how I had to do it, because I realised I had this whole palette of physical shapes.

"So if I just wrote 'they eat each other', I knew they would do it very beautifully and very athletically, and so there are a few moments where I don't have to write anything at all."

Bryony went away and responded to the Frantic Assembly style and to the story too. "I decided I had to be equally eloquent with my writing as a difficult subject had to be supported with huge style."

Words and physical theatre merge in the darkest of places.

"We're going very dark this season? I'm the head of dark at Frantic Assembly, " says Bryony, relishing the prospect of a story where a couple love each other to bits rather too literally.

"What we learn about love from this play is as always just to watch out. I had a phrase in my head the whole time I was writing, which was that love is about letting the airs of heaven blow between you.

"When you watch this play you're watching beautiful bodies and it's very attractive to watch until you think, oh my goodness. It's like a neighbour watching two neighbours and hoping they're not going to destroy each other."