City academies are producing better results than similar schools and are proving so popular that there are three applications for every place, new research finds.
Education secretary Alan Johnson welcomed the new application figures and the latest evaluation report from PricewaterhouseCoopers (PWC) as proof that the semi-independent state schools were working.
But the financial firm's report also finds city academies expel a "significantly higher" proportion of pupils than in the rest of England - on average 0.7 per cent compared to 0.25 per cent - prompting concern that they are getting rid of their most difficult pupils.
Critics of the academy programme, which the government hopes will result in 200 of the schools being set up by 2010, also point to a fall in the proportion of children from poorer backgrounds attending the institutions, from 44.5 to 44.1 per cent from 2003 to 2004.
Today's report is the third instalment of a five-year analysis of city academies, which are set up on the site of underperforming inner-city secondaries at a cost of £25 million, £2 million of which comes in sponsorship from individuals, charities or other groups.
They have proved highly controversial, with critics arguing that with the influence of outside bodies, the extra resources they have access to and a wealth of new freedoms - particularly from the national curriculum - they are privatisation by stealth.
But today Mr Johnson said he was "delighted" by the PWC report's recognition of the "considerable good work" going on throughout the programme, backed up by government figures showing a 30 per cent rise in applications this September.
"Parents want to send their children to academies because they want their children to succeed. Academies work and are wanted," the education secretary said.
The PWC report finds pupil performance at key stage three and four has been improving, often at a faster rate than comparable schools, although it says the "absolute difference" between the schools is generally small.
Some academies recorded a fall in performance, and four out of the 11 studied were below the national average, but the report notes this is generally when the positive factors highlighted in the top academies, such as strong and consistent leadership, were lacking.
And despite the fall in the number of children on free school meals attending city academies, it says that on average they still take more children from disadvantaged backgrounds - and with special educational needs - than other schools.
The report does raise concerns about relationships between academies and other local schools - only 48 per cent of staff said their academy offered support to other institutions in the neighbourhood, and even less said they regularly took part in LEA initiatives.
Almost one fifth also said their academies "proactively" recruited good students from neighbouring schools, an increase of two percentage points on last year.
"The government's creation of a group of institutions that are funded more generously and which are isolating themselves from other schools is leading to a divided and fragmented education service," said NUT general secretary Steve Sinnott.
"This will not promote social cohesion nor will the government live up to its claim that every child matters.This privatisation by stealth will not benefit this or future generations of children."