It all came to a head last week when we stopped Louise going to the school prom. She had been warned about her behaviour. The rest of Year 11 had no difficulty picking up the message. Louise ignored the warning so had to face the consequences. But Mrs Jones was having none of it. Too harsh, not fair, not her fault, give her another chance. What? Again?
It was a stormy meeting but we stood our ground and a tearful Mrs Jones stomped out of the school. This will be the last time we will ever see her in school, for Louise is leaving now. It is not the note on which we would want our relationship to end. But we are relieved that we will not see her anymore, fighting Louise's corner in desperate irrationality.
So why does Mrs Jones refuse to confront what Louise has become? After all she is articulate, employed, smart and competent.
The answer is extreme compensation for an unpleasant divorce that still hurts. Louise, confused and trapped between warring parents, must be protected and supported. Now she fights for Louise unreasonably, ignoring what her daughter has become.
So Louise knows that all things are possible and permissible. Of course she does not truant - she was ill. She does not smoke, does not swear. She did her homework. The teacher lost it. The teachers pick on her all the time.
And so it goes on.
There are many parents who believe that teachers have nothing better to do than pick on their children, as if we have the time or the inclination to single out an individual with the sole purpose of making their life difficult. In fact, teachers are far more tolerant than they should be.
To immediately spring to a child's defence, no matter what, is to commit a great disservice to them. Children need boundaries within which to begin to run their lives. Without them they are adrift.
I see more clearly than Mrs Jones what her daughter has become. Louise puts herself repeatedly at risk through her behaviour. She is a promiscuous, heavy-drinking, chain-smoking time-bomb. And one day she will explode.
Ian Roe is a secondary teacher in north Wales. Names have been changed to protect confidentiality