This is what a world without it looks like:

Karen Andrews can't speak. Every time she starts to tell her story, she puts her head down and crumples. She is slim and angular and has the faded radiance of the once-rich, even though her clothes are as creased as her forehead. I find her in the car park of one of Dubai's finest international hotels, where she is living, in her Range Rover. She has been sleeping here for months, thanks to the kindness of the Bangladeshi car park attendants who don't have the heart to move her on. This is not where she thought her Dubai dream would end.

Her story comes out in stutters, over four hours. At times, her old voice - witty and warm - breaks through. Karen came here from Canada when her husband was offered a job in the senior division of a famous multinational. "When he said Dubai, I said - if you want me to wear black and quit booze, baby, you've got the wrong girl. But he asked me to give it a chance. And I loved him."

All her worries melted when she touched down in Dubai in 2005. "It was an adult Disneyland, where Sheikh Mohammed is the mouse," she says. "Life was fantastic. You had these amazing big apartments, you had a whole army of your own staff, you pay no taxes at all. It seemed like everyone was a CEO. We were partying the whole time."

Her husband, Daniel, bought two properties. "We were drunk on Dubai," she says. But for the first time in his life, he was beginning to mismanage their finances. "We're not talking huge sums, but he was getting confused. It was so unlike Daniel, I was surprised. We got into a little bit of debt." After a year, she found out why: Daniel was diagnosed with a brain tumour.

One doctor told him he had a year to live; another said it was benign and he'd be okay. But the debts were growing. "Before I came here, I didn't know anything about Dubai law. I assumed if all these big companies come here, it must be pretty like Canada's or any other liberal democracy's," she says. Nobody told her there is no concept of bankruptcy. If you get into debt and you can't pay, you go to prison.

"When we realised that, I sat Daniel down and told him: listen, we need to get out of here. He knew he was guaranteed a pay-off when he resigned, so we said - right, let's take the pay-off, clear the debt, and go." So Daniel resigned - but he was given a lower pay-off than his contract suggested. The debt remained. As soon as you quit your job in Dubai, your employer has to inform your bank. If you have any outstanding debts that aren't covered by your savings, then all your accounts are frozen, and you are forbidden to leave the country.

"Suddenly our cards stopped working. We had nothing. We were thrown out of our apartment." Karen can't speak about what happened next for a long time; she is shaking.

Daniel was arrested and taken away on the day of their eviction. It was six days before she could talk to him. "He told me he was put in a cell with another debtor, a Sri Lankan guy who was only 27, who said he couldn't face the shame to his family. Daniel woke up and the boy had swallowed razor-blades. He banged for help, but nobody came, and the boy died in front of him."

Karen managed to beg from her friends for a few weeks, "but it was so humiliating. I've never lived like this. I worked in the fashion industry. I had my own shops. I've never..." She peters out.

Daniel was sentenced to six months' imprisonment at a trial he couldn't understand. It was in Arabic, and there was no translation. "Now I'm here illegally, too," Karen says I've got no money, nothing. I have to last nine months until he's out, somehow." Looking away, almost paralysed with embarrassment, she asks if I could buy her a meal.

She is not alone. All over the city, there are maxed-out expats sleeping secretly in the sand-dunes or the airport or in their cars.