''In my 'cage' in Shamshuipo there were about 40 people living in 700 square feet,'' Mr Go, 26, said. ''And that is about half the number that lived there 10 years ago. Their average rent was around $300-400 per month.

''There are many old people living there, mostly single. Some had family on the mainland and sent money back home.

''They worked in Chinese restaurants or as 'coolies', but a large number were unemployed, often because of industrial accidents,'' he added.

''They can't afford to live anywhere else once they can't work. Some have lived there for years.'' Social workers regularly visit the cages as many of the poverty-stricken tenants are addicted to drugs and alcohol. Many also suffer from mental illness.

Conditions are cramped, dangerous and often insanitary. Many inmates have cats to combat the rats. The beds are infested with fleas.

''It smells very bad in there, especially in summer,'' Mr Go said.

''In the beginning when we went inside the cage it was very difficult, because most of them are old and care very much about their privacy.

''They would see the camera as a weapon. So I tried to gain their confidence one by one. I wanted them to trust me, to get used to me.

''They gradually let me take pictures but sometimes they were still scared. They were worried about what we were going to do with the pictures - give it to the Government or something.'' Most cage people keep their families in the dark because they are ashamed of their plight, he said. ''They kept telling me they weren't worth photographing and that they were ugly.'' The photographers were backed by the Society for Community Organisation, a charity that campaigns for better housing. The exhibition, entitled Cageman, opens on September 3, at the Hong Kong Arts Centre.