When the changes were first mooted nearly two years ago, ministers said they wanted to cut down on the prescribed programme to leave teachers free to target lessons at pupils of different abilities. It all fitted well with the belief that personalised learning was the answer to our educational ills. It also acknowledged the force of teachers’ arguments that they would teach better and that standards would improve if they had more freedom to decide what they taught.

But the temptation to interfere has proven too great. Ever since the national curriculum was introduced nearly 20 years ago, governments have tried to pack it with topics that reflected fashion and personal preference. Margaret Thatcher fought for a greater emphasis on British history. David Blunkett agreed to keep the controversial Chris Woodhead in post in exchange for the introduction of citizenship lessons. Charles Clarke was keen on life skills, though his enthusiasm for shirt-ironing is not yet reflected in the timetable.

The crowded curriculum stems from the mistaken belief that society’s difficulties can be solved by schools. As John Dunford, the secondary heads’ leader, says in this week’s TES, it is often the result of ministers reacting to whatever is in the newspapers that month. Headlines about junk-food and obesity? Try cooking lessons. Having a spot of bother with multiculturalism? How about some instruction in what it means to be British?

Few people would support a return to the days before the national curriculum. But governments should keep prescription to a minimum. They should also realise that if they want to put a topic in, then they have to take one out. A TES poll last autumn showed that an overwhelming majority of teachers believe that the present curriculum is unsuitable for many pupils, and that more flexibility to tailor lessons to individuals would improve behaviour. It is time to listen to them.