Speaking from my own experience all I can say is that choosing to live on the streets is a last resort. I had a serious drug problem and no hostel would take me and if they did drugs came before rent. In the sixties no one saw drugs or homelessness as a problem until the late William Shearman and a few friends who founded Crisis the charity for the homeless saw it as a problem. So he and a few friends started to show people just how great a problem this country had. It's quite funny because even they thought it a problem that could be fixed in a couple of years. Had they known how big a problem it was then maybe things would have been done differently but thirty years later the problem has gotten worse and crisis has gotten much bigger.
Politics does play a part in the cycle of homelessness and poverty? Governments need to understand people more. It need to take into account that not everyone is the perfect member of society. Some are lets say slightly flawed. It needs think about policies much more before introducing them, like ID cards how are people on the breadline are going to be able to afford one? When they are already struggling to make ends meet as it is. To me it's just another way a person can become homeless. If you look at things sensibly and just take one of things you can actually be taken to court for today, no TV license £1000 fine or go to jail and who wants to go to jail?