Now 23, Andy has lived rough almost constantly since being shown the door at the now closed Dick Sheppard school in Lambeth.
He admits he was bored by school and marked out as a troublemaker early on.
He says: "I used to sit down in class and write one line - my name and the date, and then start messing about. I had one teacher who helped, he told you where you were going wrong, but the rest didn't care.
"When I got kicked out - that was it, nothing. One of my mates got kicked out at the same time, he got sent to a pupil referral unit. He got paid to go this unit and make birdcages."
With nothing to do but hang around, Andy says he quickly went "from bad to worse".
"I started on drugs, pot, E, cocaine. Once you get there it's a vicious circle, nick, smoke, nick, smoke. My mum couldn't cope with the police coming round with warrants, so I had to leave. After that it just collapsed. I had my first of three jail sentences at 18."
Today, thanks to the help of a street youth worker from The London Connection, a young homeless project in London's Covent Garden, Andy is free of drugs and living in a hostel.
Intelligent and articulate, Andy has just applied to study sport and leisure at Hackney college, and has ambitions to be a personal trainer.
"If you don't have an education, you only get the rubbish jobs no one else wants. Someone's got to do them, but I don't want it to be me any more. I want an education."