Schools included on a so-called "name and shame" list by the education watchdog have lost almost 600 staff since 2015, a union has said.
Research by the National Education Union (NEU) found 216 classroom teachers and 133 teaching assistants were among the 599 positions no longer filled over a two-year period at 124 schools highlighted by Ofsted, according to the Government's own workforce figures.
Kevin Courtney, joint NEU general secretary, said: "Ofsted's chief inspector says that no child should be cheated out of the future they should and could be aiming for – the reality is sadly very different.
"Putting out lists naming and shaming these schools is neither fair nor helpful and can lead to difficulties in recruiting and retaining teachers – something that Ofsted and Government need to address.
"It is clear that the 'support' these schools have received is not working, and raises a significant question about the effectiveness of the current inspection regime.
"The real needs of schools serving different communities will not be met until the Government conducts a comprehensive and objective assessment of those needs and fully resources them.
"This will require reversing the vast cuts that have occurred."
Mr Courtney said the schools had "some of the most deprived children in the country" with 43 per cent of their pupils identified as being eligible for free school meals – considered a key indicator of poverty – in the previous six years, compared with the national average of 26 per cent.
The Ofsted report found that overall, education and care provided to young people is "better than ever", with around 90 per cent of primary schools and 79 per cent of secondaries rated good or outstanding.
A Department for Education spokesman said: "The new National Funding Formula, backed by £1.3 billion of additional investment, will mean all primary schools receive £3,500 per pupil and all secondary schools £4,800 per pupil by 2019-20.
"As the independent Institute for Fiscal Studies has confirmed, overall schools funding is being protected at a national level in real terms per pupil over the next two years.
"This government's reforms are raising standards for young people, as evidenced by the nine out of 10 schools now rated good or outstanding and 1.9 million more children being taught in these schools than in 2010.
"We are continuing to tackle consistent under performance by investing £280 million over the next two years to target resources at the schools most in need to improve school performance and deliver more good school places, and £75 million for teachers' professional development."