I turned to see a young man smoking a cigarette and carrying a rucksack. He told me he was on his way to see if he could get into the homeless shelter down the road. He was, he said, suffering from Paranoid Schizophrenia and would probably be sectioned. He rolled up his sleeves to show me wounds on his arms. He had, he said, been begging outside one of London's top hotels that day and had made £18.
Over the next 20 minutes or so, in that dark street, he told me a lot of things about his life. Some made sense, others maybe less so. He told me his name but it wouldn't be fair to tell you what it is, or too many details about his life without his permission.
What was clear, though, was that this was an incredibly vulnerable young man. He should have decent help and support. He should have a guaranteed place to live.
There's supposed to be a safety net for people in need. It doesn't catch everybody.
Countless times I've seen politicians outline what should happen at a hustings, for example. One which comes to mind was the SAMH hustings on mental health provision ahead of the 2011 Holyrood election. It soon became obvious that there was a monumental gap between what the politicians thought was happening and what people were experiencing on the ground.
The young man I met the other night was very keen to make sure I got safely to the tube station. I just wish that there was something I could have done for him, to make sure he was safe.
When people are being left to sleep on the streets and are not given the medical care they clearly need, something is going wrong somewhere.