More than one-third of schools in the government’s academy converter programme have cited additional money as their primary reason for taking part, according to a survey of almost 500 of them.

The findings are in contrast to the government’s claims that schools were not converting to academy status to receive extra funding. Academy institutions, funded directly by the central government as opposed to local authorities, are supposed to be financed at the same level as other local schools.

The government has claimed converters were seeking the extra freedom associated with the status, rather than the money. Officials had intended to give them the same amount as other schools but most were accidentally overpaid.

Since May 2010, 1,298 have chosen to become converter academies, seeking the status of their own volition. A further 337 are “sponsor” academies or schools turned into academies and placed under the control of a third party as part of a sustained effort to improve standards.

The survey, by Reform, a pro-market think-tank, and the Schools Network, a membership organisation comprising 5,000 schools, found that two-thirds of converting schools had used their freedom to change the curriculum or planned to do so, relishing their greater autonomy over teaching and pay.

The academy scheme is the coalition’s central reform programme, intended to devolve more autonomy to schools and drive up standards by increasing competition between institutions.

Sue Williamson, Schools Network chief executive, said: “Many of these schools have only been academies for a few terms yet are already improving the curriculum with ideas such as replacing ICT [Information and Communications Technology] courses and [offering] new languages. Many are also looking at changes to the school year.”

Schools have, however, shied away from using their ability to vary salaries, with 65 per cent saying they did not plan to do so. This mirrors the reluctance of local authority schools to use their more constrained rights to vary pay.

The survey suggests that while some authorities have very poor relations with local academies, most manage to maintain their good links: 68 per cent of converters said there had been no change in their relationship with the borough and only 15 per cent said the relationship had deteriorated.

Furthermore, 25 per cent of schools said their relationships with other local schools had improved post-conversion. Dale Bassett, research director at Reform, said the results “explode the myth of anti-academy campaigners that academies would lead to the disintegration of the state education system”.

Overall, the survey found 84 per cent of academy leaders would recommend the change of status. Bill Watkin, operational director at the Schools Network, said: “We believe passionately in the power of school autonomy and effective school-to-school collaboration.”