Half of the government's city academy schools are among the "worst performing schools" in Britain.
The effectively part-privatisation schemes are costing UK taxpayers £5 billion.
Of the 14 academies open long enough to be included in the leagues tables, seven are among the 200 lowest performing schools, based on the proportion of pupils achieving five or more good passes at GCSE.
Typically, fewer than three in ten pupils at the under-performing academies achieved five good passes. At Bexley Business Academy in Kent, the first city academy, 29 per cent of pupils achieved five good passes, an achievement attained by 16 per cent of pupils at Middlesburgh's Unity City Academy.
Figures also show that truancy rates at some city academies are five times the national average.
However, a spokeswoman from the education department maintained that city academies are making strong progress, arguing that attainment was higher in the academies than in the failing schools they had replaced.
In the face of the figures, Steve Sinnott, general secretary of the National Union of Teachers, has called on the government to reconsider its policies for failing schools.
"Handing over children's education to individuals or organisations that are willing to stump up £2m is not a panacea for the problems faced by schools in challenging areas," he said.
"The government now wants to create a huge pile of trust schools which are little different from academies. It needs to stop and think and examine the evidence."
Edited from the NUT: