At the centre, my deputy is sitting on the doorstep surrounded by other students. Her handbag (containing the door keys) was stolen from her husband's car last night. She and I enter - followed by the now-augmented throng - to the ringing of the phone.
Monday mornings are as likely to find our students locked in a police cell as barricaded inside their bedrooms, so the sound of the phone is not uncommon.
But the call is from a mother. She wants to thank me for the reference I wrote for her son. It is the only reason he has not been locked up, according to her son's solicitor. I am unsure how to respond to the compliment.
How can I explain that I write what I see - that if I write a glowing report on a student known to be a tearaway, when the next report is read out in court it will be treated with the contempt it deserves; that I haven't perjured myself for the sake of her son. The reports I write for court officers (with alarming frequency) are shared by the staff team, who comment and recommend changes from time to time in the light of their contact with our students. After all, we each have our own perspective.
I have to feign some sort of crisis to avoid making a proper response to this mother. Trying to explain the need for honesty in my report will only aggravate her sense of personal failure. Last week she told me someone from the court had visited the family and suggested she go on a parenting course. "I'm 49," she told me. This revelation was followed by her belief that having brought up three other children, she didn't need a parenting course. After all, the other three had grown up all right.
The Youth Offending Team member who visited the family also phones me. Her description is of a woman out of touch; a mother in need of help, reassurance and some new ideas.
Later I have to collect the lad for his afternoon at the centre. He gives me a broad grin and thanks me. "It means going to the attendance centre again," he says. "That'll be my third first aid certificate," he announces proudly. Same process. Same programme. Same result?
As his mother waves us goodbye, I wonder if the upbringing of her first three was as stress-free as she describes it. Even if it was, my colleague from the Youth Offending Team is right - there stands a woman out of touch. Her other children are all over 20 and all married. She is a grandmother.
Her youngest son is a child of the Nineties. More importantly, he is who he is - an individual, not a clone. He responds to us, why doesn't he respond to his mother? It is a question many teachers and workers with young people must ask themselves every day.
I look back at my own children - now grown and married. Each had his or her own personality. Each had to be approached in a unique fashion. Each reacted differently to our requests and suggestions. Each, I would hope, was treated as an individual at home and at school.
As I drive home from the centre, the puzzle stays in my mind. Did my training as a teacher make me a better parent? Or was it being a parent that made me a better teacher?
Could this be the basis of some MEd dissertation? "The OFSTED rating of classroom teachers is directly proportional to the number of children they and their partner have spawned, dragged through teenage and are still talking to."
Evaluate without the aid of a selective memory and rose-coloured spectacles.
The writer, who wishes to remain anonymous, is head of a pupil referral unit in East Anglia Anonymous