Compared to other countries England does well with pupils at the top end of the ability spectrum - they succeed academically and go on to excellent universities, according to OECD Pisa studies. But we do badly, compared to other similar countries, with the lower end of the spectrum. So education in England is on average quite good, but this average conceals a huge range.

In England, we have lower levels of literacy and numeracy among the bottom 60 per cent of young people than most of our competitors. Even those who pass GCSEs often have low levels of literacy and numeracy, as do some of those going to university. Many students going to university to study non-vocational courses will emerge with big debts but will find it impossible to acquire graduate-level employment. 

We have much lower levels of technical training post-16 than most of our competitors, particularly at intermediate skills level. As a result, we have low levels of productivity per person. A huge proportion of the English population are in low skill jobs and on low pay.    

The 1960s baby boom means that a large part of the skilled workforce will be retiring in the next few years. As they retire, the country will struggle to replace them. For example, Engineering UK estimated last year that the UK will need 182,000 new engineers a year between 2012 and 2022, mainly to replace those retiring. At present we produce 113,000 a year. 

Brexit may mean a decline in skilled workers coming from the EU; we do not yet know if we can compensate by attracting equivalents from outside the EU.

We talk a huge amount about school systems - the merits of academies versus maintained schools, free schools, grammars, independent schools. But 80 per cent of the difference in outcomes between pupils occurs within schools as opposed to between schools. How well your child does at school depends very much on the individual teachers they have, not just on the school they go to. Teachers are what matters. This is why we need to focus much more than we are on recruiting and training good teachers.

Universities, think tanks and the government talk a huge amount about how unfair the system is to pupils from poorer homes. It is true - pupils from poorer homes clearly need more support. But over three-quarters of those who fail to pass five GCSEs including English and maths are not on free school meals. And the focus on equality of outcomes obscures an even more important issue, about which we hear little: the low average level of knowledge of almost all our children. 

We are one of the very few countries in the world where young adults have weaker literacy and numeracy that adults of retirement age. As the OECD recently reported, “the evidence points to upper secondary programmes in England which require lower levels of basic skills than many other countries.”

I went to visit schools around England, primary and secondary, which either get incredible value added scores for disadvantaged pupils or who have improved dramatically in a short time. All these successful schools have the same formula; here are some examples:

• They have quite strict discipline, without which nothing excellent can be achieved.  Children need clear rules which are firmly enforced and on the whole they prefer that to the alternative. Parents are required to support these school rules. 
• They require all pupils to do well regardless of their background, gender, ethnicity or special needs. This means they set high standards and any pupils who fall behind are immediately required to have extra tuition and work harder. They believe that the limits to learning are not set by intelligence but by effort, the effort put in by both the pupil and the teacher.
• Expectations are not limited by target grades or by a special needs label. Target grades are just as likely to demotivate a child as encourage them to work harder. The best teacher at a comprehensive school I visited said: “I ignore the school’s target grades because my target is a top grade for every child. I will not achieve that, but MY targets influence everything I do.”

At good schools, pupils learn how to commit work to the long-term memory because if material is committed to memory it makes it much more likely they will have both a better understanding and think analytically.

And good schools are led by head teachers who pursue these simple goals and don’t get diverted by other issues. They keep it simple; they are focused. 

Much Promise: successful schools in England is published by John Catt this month.

Barnaby Lenon is a former head of Harrow school and chair of the Independent Schools Council