The Department for Education this year approved only one in five applications to open Islamic and Hindu faith schools as part of the government's flagship free schools programme, while accepting applications from two out of three mainstream Christian faith schools, based on analysis of data released under a freedom of information request.
The data also showed that the DfE accepted only 102 entrants from 263 applications to open free schools from September 2014, in the fourth wave of free school openings since the policy was launched by the education secretary, Michael Gove.
A comparison of the failed and successful applications showed that efforts to start 18 Islamic faith schools were rejected by the DfE, while six were accepted. Seven applications to open Hindu faith schools were turned down and none succeeded.
In comparison, 16 Christian, Church of England and Catholic faith schools were approved, while nine were rejected.
A DfE spokesman said: "It is quite rightly difficult to set up a free school and it has always been the case that only the strongest applications get the go-ahead."
Of the 2014 applicants, roughly a quarter were to establish faith schools. A third of maintained state schools have a faith designation, the majority of which are Church of England schools.
The details of the free schools programme – including the DfE's internal assessments as well as spreadsheets showing the opening costs of the schools – were published after a long battle by the DfE to keep the information secret.
In a combative letter to Christopher Graham, the information commissioner, Gove sought to explain why the DfE fought disclosure, saying: "We wanted to protect public-spirited volunteers from intimidation".
"In some cases these have become highly personal, vilifying individuals involved in opening a free school. We have been told of instances where teachers have lost their jobs simply by virtue of their association with a free school application. One proposer has even told us that they have been the subject of a death threat," Gove wrote.
The release included spending on the start-up costs of the schools. It included £430,000 spent by the DfE on seven free schools projects that later had the plug pulled, in most cases by the DfE itself.
"David Cameron and Michael Gove have wasted hundreds of thousands of pounds on free schools that haven't even opened. And millions of pounds have been spent on free schools which are being set up in areas where there isn't a need for new places or demand from parents," said Stephen Twigg, the Labour shadow education secretary.
The DfE responded: "We make no apologies for spending money on encouraging new people to come forward, offering new ideas and new ways to run schools. This process has a cost but the cost of educational failure is vastly higher."
The approval rate of just two in five suggests the DfE could struggle to reach a target of opening 180 new free schools in 2015-16, as outlined by George Osborne in the comprehensive spending review this month.