2. It's very difficult to judge the impact of one teacher. Even if results were entirely down to everything the teacher did (and clearly they are not), what happens when the teacher is given a new GCSE group from year 10 that has been badly taught for the previous three years? Again, it is impossible to judge. And what of those teachers who don't have any exam groups? Set them targets saying pupils must make two sub-levels of progress by the end of the year and the teacher will simply award those children the results you've demanded. Results are not an accurate way of measuring teacher performance because they can literally just make them up.

3. Pupils are responsible for their results, not teachers. The culture in state schools is already upside down. Visit a good private school, and the children will tell you that they get good grades because they work hard. If they got a bad mark, it's because they were slacking. Kids in the state sector think that when they get a bad mark it is because the teacher wasn't good enough. Paying teachers according to results will only exacerbate an already pernicious and debilitating culture in our schools. 

4. Extra-curricular activities should be valued. A target culture undermines this. Teachers don't just teach their children to pass exams. Or at least they shouldn't. Reward them for reaching certain results and that's exactly what they'll do. Teaching to the test is already a massive problem in state schools. This goes to the heart of what is wrong with PRP. A narrow focus on targets is not what you want in a good school. Why would you want to encourage teachers to think that only a small part of their job (namely three targets) is important?

5. Intrinsic motivation is a good thing. Pay a teacher to take on that extra basketball class and suddenly the intrinsic motivation is gone, and not just from that individual, but from all of your staff. One of the beautiful things about good teachers is the way they give effortlessly for the sake of their pupils. Do we really want a bonus culture in our schools as exists in the City where 100 per cent of bankers believe they are entitled to some sort of bonus and  every year they complain about how it's too small? Welfare recipients may start out feeling grateful towards government for its help, but at some point that turns into a sense of entitlement. Is that what we want for our teachers?