A widening gap between standards in English, maths and science and pupils'
achievements in other subjects, was highlighted in his annual report.
The standstill in English in key stage 2 test scores in the past few years was also identified as a cause for concern.
In a fifth of primaries teaching remains no better than satisfactory. The report reveals that English and maths lessons are good or excellent in two-thirds of primaries, but only 45 per cent of history lessons and 36 per cent of geography lessons reach the same standard.
Mr Bell said primaries lacked the confidence to take control of the curriculum despite having the scope to do so.
"There is still some way to go in ensuring that all pupils in our primary schools enjoy a rich and fulfilling curriculum as well as being taught the basics of English and mathematics. We cannot afford, and our children do not deserve, a two-tier curriculum," he said.
Mr Bell suggested that a broader curriculum could help restart improvements in literacy and numeracy.
Chris Davis, National Primary Heads Association spokesman, said: "This is good news but David Bell needs to get his message through to inspectors.
Teams on the ground are not looking in as much detail at foundation subjects as they do at English, maths and science."
Eamonn O'Kane, general secretary of the National Association of Schoolmasters Union of Women Teachers, said: "The blame for the rigidity of what is taught in schools cannot be laid at the door of teachers.
Performance league tables and the pressure they place on schools to teach to tests lie at the heart of the problem."
As The TES revealed last month, the annual report also showed a sharp rise in the number of failing schools from 129 in 2000-1 to 160 in 2002-3. But Mr Bell urged headline writers to be cautious, arguing that schools are now expected to reach higher standards and that special measures can often act as a catalyst for improvement.
"In schools the story is one of 'steady as she goes', reflecting hard-won progress.
"There have been obstacles, and many remain, but the steady improvements in standards, teaching and leadership and management that have taken place over the past 10 years have been maintained," he said.
Encouraging progress is evident in the early secondary years where the Government's key stage 3 strategy is raising standards.
Information and communications technology in primaries, local authorities'
school improvement services and increased flexibility in the curriculum for older pupils were also praised. More should be done to halt underachievement, particularly of white, working-class boys.
Despite improvements during the past decade, a quarter of lessons are not consistently good enough to raise standards. This is particularly marked in schools in deprived areas, many of which have difficulty recruiting and retaining high-quality staff.
David Miliband, school standards minister, pledged that Ofsted's concerns would be tackled. "Personally, I have never understood why enrichment and high standards have to be opposites."
The rise in the number of failing schools had to be seen in the context of a 60 per cent fall in the total since 1997, he said.
Inspectors' verdict on colleges, FE Focus 7
On the way up
* Secondary schools - exam results are creeping up and key stage 3 strategy is working
* 415 outstanding schools and 122 removed from special measures
* ICT in primary schools
* Low-achieving pupils in secondary schools are helped by a more flexible curriculum
* Local authority school improvement services Could do better
* Primary schools - curriculum is too narrow and improvements have stalled
* Schools in special measures, the number has risen from 129 last year to 160
* White working-class boys
* Subject leaders - teaching? quality varies too much
* Work-based learning and literacy and numeracy teaching in colleges