"When I moved into St Mungo's Cedars Road I weighed about six stone, I was skin and bone. And I hadn't had a shower for about six months."
But as Clare herself says it has taken her a long time to get to where she is now - a mother of two, in her own flat and about to be a volunteer mentor for young offenders.
Originally from Sussex, Clare was given up for adoption at birth and lived with her adoptive parents until she was 11. Then she was moved into a care home and lived there during her early teens.
At 16 she had her first child and another at 18, both of whom she in turn gave up for adoption. She had another baby at 20, who now lives with the father, and with whom she only has limited contact.
"By that point I was into serious drugs, injecting heroin, using crack. I came up to London and ended up in squats around Brixton for about six months."
That was when a St Mungo's outreach team found Clare and asked her if she wanted to go into a hostel. At first Clare was reluctant to, but the Outreach team eventually persuaded her to accept help.
Clare moved into a St Mungo's project in Cedars Road. It was there that she had her first shower in half a year. Over the next five years she went into detox services and relapsed a couple of times but persevered. Clare stopped using heroin and succeeded in getting clean through a harm reduction programme. One turning point was finding a friend who had overdosed and turned blue.
"The people at Cedars saved my life. When I relapsed I went back and they didn't judge me. If I felt like using again, I'd talk to the workers and they would try and talk me round. The key was always talking and telling someone."
Clare had been off heroin for about three years when she became pregnant again. "I didn't want my child to grow up without a home, so I got myself together and on the list to move into my own flat. I was really lucky and was offered a good one that even had a garden. Since then, I've not looked back."
Clare has never worked but has now been accepted as a mentor helping young ex-offenders. As well as her five year old, she is now a mum to a three year old and so she's looking for volunteering and flexible work to fit around childcare.
"I shouldn't be here. If St Mungo's outreach and Cedars hadn't come along; I would have still been on the streets."