The warning has come as Ofsted published its annual report last week.
In it, the inspectorate confirms that almost nine out of every 10 schools in England are now judged to be good or outstanding.
The report confirms that at the end of August 2016, 90 per cent of England’s 16,772 maintained primary schools were judged to be in the top two categories. This compares to 69 per cent in 2011.
For England’s 3,378 maintained secondary schools, 78 per cent are now judged to be good or outstanding, compared to 66 per cent in 2011.
Overall, it means that almost 18,000 schools across England are good or outstanding – 88 per cent of England’s 20,150 state-maintained primary and secondary schools.
However, in presenting his report Sir Michael has added his voice to those raising concerns about the teacher recruitment crisis, especially at secondary level.
The report emphasises that in 2015 there were 2,500 fewer full-time equivalent secondary teachers in the system than in 2014. It also highlights previously published figures showing that in 2015/16, 15 out of 18 secondary subjects had unfilled places.
The situation looks set to worsen as well. SecEd reported last week that the latest NQT recruitment figures for 2016/17 show that only four secondary subjects hit their recruitment targets – further compounding the problems. Indeed, at secondary level in 2016/17, a total of 15,713 trainee teachers were recruited to post-graduate ITT courses – only 89 per cent of the target of 17,687.
Ofsted’s report states: “There is now considerable evidence that it is those schools in isolated and deprived areas where educational standards are low that are losing out in the recruitment stakes. Furthermore, the secondary pupil population – which has been in decline for the past few years – is set to grow.
“Ofsted’s regional directors have spoken to headteachers about the impact this is having in their areas. Headteachers in the North West, for example, have reported that there is an ‘auction’ for teachers, particularly around Greater Manchester, for hard to recruit subjects. In the South East, recruitment is proving difficult in secondary shortage subjects, particularly in non-selective schools in selective areas and those in isolated or relatively deprived parts of the region. “
Sir Michael himself added: “My advice to government is to worry less about structures and more about capacity. No structure will be effective if the leadership is poor or there are not enough good people in the classroom.”
The report came as the Department for Education (DfE) confirmed that it is to abandon its plans for a National Teaching Service.
Former education secretary Nicky Morgan launched the scheme earlier this year, promising to recruit 1,500 teachers by 2020 to work in the most challenging areas. A pilot had attempted to engage 100 teachers by September this year but reportedly only managed to recruit 54.
Commenting on the news, Russell Hobby, general secretary of the National Association of Head Teachers, said: “I think we have learned now that we cannot rely on schemes that only transfer people from one part of the country to another. We must help local areas develop, support and retain their own staff.
“One reason the scheme has not delivered is that there are simply not enough teachers in the system. We have to get the basics right – proper starting pay and good working conditions.
"The annual report from Ofsted made this clear, and our own recruitment survey released in November (Two in 10 vacant positions in the past year have gone unfilled, SecEd, November 2016) confirms that schools are struggling to recruit. This is felt by all types of schools across all regions.”
Elsewhere in this report, Sir Michael continues to raise concerns about the North-South divide, which he warns has widened slightly this year.
In the report, he states: “Last year, I highlighted the disproportionate number of secondary schools that are less than good in the North and Midlands, compared with the South and East of England. This year, the gap has widened slightly.”
The report shows that more than a quarter of secondaries in the North and Midlands are rated as inadequate or requires improvement. Furthermore, there are 10 local authorities with 40 per cent or more of pupils who are in secondary schools that are less than good, and where attainment and progress is below the national level on the key accountability measures, and all but three are in the North and Midlands.
Sir Michael added: “Standards can only truly be considered high if they are high in every part of the country and for all pupils regardless of background or ability. For children under the age of 11, truly high standards have almost been achieved. Over the age of 11, there is still much to be done.”
At secondary level, the report also makes a clear connection between school improvement, strong leadership and a focus on teacher development.
It adds: “In the schools that were found to have improved, there was a very clear pattern of improved teaching because leaders had focused on continuous bespoke professional development. Investment in highly personalised training, feedback and assessment of the quality of teaching was beneficial. Senior leaders understood clearly what staff needed to improve their teaching.”