The poorest pupils in England are nine times as likely to attend an inadequate school as the wealthiest pupils, a Labour analysis has revealed.

And within some regions inequalities are even more marked, with the most deprived children in the east Midlands 18 times more likely to go to one of the worst performing schools as their most privileged counterparts.

The findings, which Labour described as shameful, are based on Ofsted data for secondary schools covering performance and schools’ rating on a deprivation index. The party released the figures before GCSE results day on Thursday to challenge government claims that pupils generally are benefiting from higher school standards.

According to Ofsted figures for the end of March this year, 28% of secondary school pupils in England were in schools rated outstanding. Another 54% were in schools rated good, 14% were schools deemed to require improvement, and 4% were in schools rated inadequate.

Among the richest fifth of pupils in England, only 1% attended an inadequate school. But among the poorest fifth, 9% were attending one of the worst-performing schools.

At the other end of the scale the picture is reversed. Some 44% of pupils in the top quintile (the most privileged 20%) were attending an outstanding school, but only 19% of those in the bottom quintile.

Within some English regions the correlation between wealth and the chances of attending a top secondary school seem even higher. In the east of England just 3% of the poorest pupils were attending one of the best-performing schools, but 42% of the wealthiest pupils were in a school rated outstanding.

In the south-west, 43% of pupils in the highest quintile were in a top school. But there was not one outstanding school in the region where the pupils were on average among the poorest 20% or the second poorest 20%.

In the south-east, only 6% of the most disadvantaged pupils attended an outstanding school. But 41% of pupils in the highest quintile, and 29% of pupils in the second wealthiest quintile, were getting a top-class education.

In London 35% of the poorest pupils were at an outstanding school. But for the wealthiest pupils the figure was 62%, and there was not a single school rated inadequate in the capital where the pupils were on average among the wealthiest 40%.

In the north-west, 47% of the most privileged pupils attended an outstanding school and only 2% an inadequate school. Among the least privileged pupils the figures were 7% and 13% respectively.

In Yorkshire and Humber, 47% of the richest pupils were at an outstanding school but just 16% of the poorest. For the east Midlands the figures were 47% and 9%; for the north-east 45% and 5%; and for the West Midlands 43% and 23%.

Angela Rayner, the shadow education secretary, said: “No child should be held back from reaching their potential because of their background.”

The Department for Education said that since 2010 the number of pupils in good or outstanding schools had risen from 66% to 86% and that £2.4bn a year was being spent specifically helping disadvantaged pupils through the pupil premium.