Primary schools condemned as failing are overwhelmingly those in areas with high levels of poverty, according to new figures from the Office for Standards in Education.
They show that the poorest 10 per cent of schools in the country are eight times more likely to fail their inspections than schools with average levels of poverty or better.
This clear link between poverty and failure contradicts a recent claim by HM chief inspector, Chris Woodhead, that deprivation only affects a minority of schools placed under "special measures".
Writing in The TES last month, Mr Woodhead said that "it is not only - or even mainly - primary schools with deprived intakes which fail inspections".
Statistics just released by his own department show that the poorest third of primaries account for as many as 70 per cent of failing schools. The poorest tenth makes up nearly 40 per cent.
The figures have emerged at a time when Ofsted is promising to scrutinise "coasting" schools - those with good pupil intakes and adequate results which make little effort to improve.
While the new statistics do not identify privileged or coasting schools, they do show that the most affluent 65 per cent provided less than one third of the failures.
The Ofsted figures are based on the proportion of pupils eligible for free school meals - the standard indicator of deprivation. In practice this is equivalent to the proportion of unemployed families. Some 20 per cent of primary and 17.5 per cent of secondary pupils in England are eligible.
The findings match those of Mark Wightman at Durham University, who has established that 59 of 83 failing secondary schools had to cope with poverty levels over twice the national average. None of the failing schools was in a prosperous area.
Mr Woodhead's assertion that the majority of failing primary schools do not have deprived intakes appears to depend on a rigorous interpretation of poverty.
Writing to Dr Jim Murphy of Lancaster University, Mr Woodhead described deprived schools as those where more than half the pupils are entitled to free school meals. Schools where one-third of the children live in poverty would be excluded from this definition, seen as a "very tough" benchmark by the London School of Economics.