Sir Michael Wilshaw, Her Majesty’s Chief Inspector, writes:

For years, debate about the English education system has largely focused on structure and organisation. Endless arguments have raged about whether the comprehensive or selective model was the right one, whether grant-maintained status should be expanded or abolished, whether academies are the way to maximise autonomy, and - most recently - whether free schools are the way forward.

These issues are undoubtedly important. But I think that by dwelling too much on the type of school children attend, we can sometimes overlook the importance of what actually goes on inside the school. I say that because what determines success or failure, above all else, is the culture of the school.

In my speech to launch Ofsted’s Annual Report, I was pleased to be able to say that the system has made marked improvements in the last year - much of it down to better teaching. Seven out of 10 lessons observed by inspectors this year were good or outstanding - although quality varied across key stages and year groups, as well as from one part of the country to another.

So while there is much to celebrate, serious challenges remain. One of the factors impeding England’s progress is that too many schools are still failing to instil the right learning ethos in and outside the classroom.

More than 40 years’ experience in tough inner-London schools brought me to understand the importance of making sure teachers can get on with the business of teaching. Good behaviour underpins everything else. While we now rarely encounter the sort of serious mayhem that characterised some schools in previous years, we haven’t yet tackled what I called in my report a casual acceptance of low-level disruption.

Making sure all of our classrooms are calm, respectful and orderly places is crucial. It’s especially important for the most disadvantaged children, who often lack boundaries at home and for whom school can provide the only security and structure they know.

I talked last week about “lucky” and “unlucky” children - of an educational lottery in which two children from the same background and the same ability end up on divergent paths. The lucky child, nurtured at a great school led by an outstanding headteacher, fulfils his potential. The unlucky child, born in an area where expectations are already low, suffers because his school has a sloppy attitude to learning. His lessons are undermined by background chatter, inattention and horseplay.

That’s why in the New Year, Ofsted will be focusing more closely on school culture and behaviour. In this context, I announced that, from January, inspectors will make no-notice visits to schools where we have identified behaviour as a particular concern. I view this as the next key challenge in raising standards for our children. So I was encouraged to hear a number of serving headteachers in challenging schools responding positively to this new emphasis - and to my call to do something about low-level classroom disruption.

Additionally, I called for the government to reintroduce formal external testing at Key Stage 1 and Key Stage 3. I believe that it is vital for parents to know what progress their children are making at regular intervals in their school career. This is even more important with the proposed abolition of national levels around the corner. I think it’s a salutary lesson from the recent Programme for International Student Assessment (Pisa) study that one of the top European performers was Poland - a country that is extending rigorous national testing.

There are certainly challenges ahead. But I also want to reflect on just how far we’ve come as a nation. I said very clearly in my report that the battle against mediocrity in our school system is gradually being won. We have the best generation of teachers and school leaders ever, and the improvement in the number of schools judged good or outstanding this year has been hugely encouraging. In the year ahead, I’ll look forward to working with the teaching profession to secure even higher standards for all our children - not just the lucky ones.