It takes a lot to make me cross. I am a typical primary teacher - passionate about teaching children to the exclusion of much that is worldly. Not political, although I do listen to Radio 4, and I read the Telegraph every Saturday.

But I was on my way to the doctor’s one morning when I heard a comment that made my blood boil. I swore at the sheep, ranted at the tractors and harangued the mothers taking their children to school. I was cross.

I was once told on a management course that listening is a vital skill. To keep this skill sharp, you should train yourself to listen to the weather forecast on the radio. Apparently, we all start off intending to listen, but drift away after the first few seconds. Listening to Radio 4 in the morning is a similar experience for me. I intend to listen so I can become an informed consumer, but my mind wanders as I plan an assembly or devise a performance management timetable. So I can’t recount the whole of the interview that raised my blood pressure. I don’t even know who was talking.

All I know is that one crass comment blew me away.

The conversation was to do with university places, another topic that incites me to violence. But I wasn’t listening properly because I’ve already suffered over that lost cause. The comment I heard was: “When 25 per cent of children leave primary school unable to read and writeI” I didn’t hear the rest because the red mist had descended.

Twenty-five per cent of children do not leave primary school unable to read and write; 25 per cent may fail to reach a benchmark on one day in May when they sit their key stage 2 tests. How many children fail by one or two marks? Does that mean they can’t read, write or calculate? No. They can discuss personification, write letters of complaint and read a graph. They are not failures.

Inevitably, there will be some children who, for whatever reason, cannot make the average. Otherwise the word average would not have been invented.

We all celebrate when these children achieve level 3. We work hard to find out what they are good at and to build their self-esteem. We prepare them for life in an ever-changing world and do not torture them because, on one day in spring, they fail to reach level 4.

With all the current discussion on transforming learning and autonomy, how dare politicians make throwaway comments that undermine all the hard work undertaken by teachers, headteachers and children? How demoralising. The director of the Government’s standards and effectiveness unit, David Hopkins, said at a conference last July: “Unless we actually do something about the accountability framework, then all of this talk about transformation, all of this talk about creativity, will come to naught.”

Hear, hear.

Fortunately, the doctor did not take my blood pressure when I reached the surgery.

Val Woollven is head of St Andrew’s CE primary, Plymouth