My worst parent started off by being my best parent, which goes to show that you never can tell.
I worked in a primary school in an idyllic village, and thought I had it made. The school was hugely valued, the kids were mostly from comfortable backgrounds, the staff were tight-knit and well-led. We had all the boxes ticked; even Oftsed loved us.
Parents were keen to get involved. One of them became a tower of strength - always the first to volunteer. She was enthusiastic, competent and, given her lofty social status (her husband was Something in the City), refreshingly deferential.
Then I noticed that the relationship was changing. At first she would follow instructions, then she began to question. If she did something in "her way", it was usually over-the-top.
She began to show initiative, like re-arranging a classroom display without being asked. And she would turn up on a whim and expect to be listened to.
Eventually, I had to challenge her and she went berserk. She used language that would be inappropriate in a rugby club, let alone a school playground, and the head had to almost physically intervene. I realised she was used to getting her own way.
She withdrew her daughter and sent her to a preparatory school. My professional pride was restored and I realised that, in the classroom, there is only one boss.
The writer is deputy head of a primary school in Kent.