Homelessness, and the stigma attached to rough sleeping, is not just a 'Developing World' issue. In cities across the world, from New York to St Petersburg, homeless people are often cast as scroungers. But many are the unlucky victims of rocketing rents, family break ups, mental health problems, addiction or shifting political agendas.

In the last of our 'Streetwise' series, we listen to what these people have to say and take a look at the organisations and networks that are helping them get off the streets.

New York, US

New York has been a magnet for those in search of the American Dream. Banks here have some of the world's richest clients. But where do the majority of New Yorkers live and what happens if you're not a Wall Street banker?

For low-income families, 'the projects' - blocks of affordable public housing - are home. But the housing market is in crisis. Following the New York City Housing Authority's decision to turn over the operation of its properties to private management firms, many have fallen into disrepair and have been boarded up or torn down. The shortage of affordable housing means that hundreds of thousands of families wait for years on the city's housing waiting list to be re-homed or camp out at the Emergency Assistance Unit (EAU).

Maria Forbes works for the Clay Avenue Tenants Association and has been living in public housing for six years. She believes that shelter is a basic human right across the world, which should be written into law.

Bristol, United Kingdom

From the outside, Bristol - one of Britain's largest cities - has a genteel problem-free image. In reality, it has the second highest number of homeless and vulnerably housed people in the UK. It also has a large population of rough sleepers.

In England, around 25% of people become homeless due to a failed relationship and 30% find themselves on the streets after friends or relatives can no longer put them up. With no address it's hard to get work and government benefits and once on the streets, escape for many is alcohol and heroin. Around 80% of rough sleepers are addicted to alcohol or drugs.

But grassroots organisations like Groundswell are helping to bring people traditionally excluded by society together. By providing a space for people to meet, share experiences and support each other, Groundswell, and organisations like it, is providing positive solutions out of homelessness and poverty.

Prague, Czech Republic: capitalist since 1989

During the communist era there were no official 'homeless' in the Czech Republic. Rents were cheap and high-rise blocks provided accommodation for every worker. But many have forgotten that conditions were far from perfect with several generations of one family crammed into one flat.

Now, just as in the United States, people are worried that there isn't enough political commitment to public housing and many fear being made homeless.

A new law may soon de-regulate the rent system leaving landlords with the power to set their own rates. Many people fear that rents will rise so sharply that thousands of people will no longer be able to afford their homes.

St Petersburg, Russia

Just as in the Czech Republic, homelessness in Russia is a relatively 'new' phenomenon. But here, the situation is spiralling out of control with a new class of mafia-style landlords ready to cheat people out of their homes.

While in New York and Prague, lobbying may yet safeguard public housing; in St Petersburg the immediate issue is how to rebuild self-esteem among people who've suddenly lost everything.

In St Petersburg at least 8,000 people are homeless.

'Rock Bottom' (also known as 'The Depth') is one of a worldwide network of 36 street papers, which are sold to the public, on the street, by the homeless. The project provides rough sleepers, or vulnerably housed people, with work, an income and badly needed self-esteem.

As in Bristol, the solution seems to lie with people-driven initiatives where the homeless find the answers themselves.