The introduction of free schools does not lead to diversity in education because large chains end up dominating the market, a senior Swedish trade unionist has warned.
Fredrik Mandelin, a senior officer at the Swedish teachers' union Lararforbundet, has spoken out about the "free schools" revolution in the Scandinavian country, which began in the mid-1990s, and which has inspired Tory education policy here.
While schools were initially set up by special interest groups with a variety of educational approaches, big companies have since become the main players, Mr Mandelin said.
Mr Mandelin, who was in England to speak to the TUC conference on the future of Britain's schools, told The TES: "In Sweden, there were these hopes that free schools would lead to pedagogical diversity, but we haven't really seen that.
"There are a relatively small number of comparatively big companies going into the free school market.
"You initially had a reform for enthusiasts, with small village schools being saved through the free schools route, or Steiner schools, but now you see growing numbers being run as an industry."
Mr Mandelin said that the profit motive in Swedish free schools had been partly responsible for the growth of chains. Education secretary Michael Gove has so far ruled that schools in England will not be run for profit?, although their day-to-day running can be outsourced to for-profit businesses.
"With free schools (in Sweden) it is relatively easy to predict your income as you have funding for each pupil," said Mr Mandelin. "If you know how many pupils you can attract you have guaranteed profits.
"It's not like if you produce Volvo cars, where you cannot be sure how much you can sell them for."
His warning echoes that of Mary Bousted, general secretary of the Association of Teachers and Lecturers, who has claimed that school chains would make money by using generic teaching materials.
Mr Gove has maintained that free schools will provide choice and diversity for parents, a view supported by many in the existing fee-charging independent sector.
Mr Mandelin's comments come after a number of leading independent school chains, including Cognita and Gems, have expressed interest in running free schools.
Marjorie Scardino, chief executive of global education publisher Pearson, recently revealed the group's continuing push into the free schools market.
However, experts in independent education doubt whether they are likely to make a profit.
David Hanson, chief executive of the Independent Association of Prep Schools, said: "The experience in the fee-charging sector is that it is difficult. Most independent schools are run on a not-for-profit basis.
"Parents do not want to see money going into people's bank accounts. I wouldn't want to see an Ikea vision of education in Britain."
Academic research released earlier this year concluded that Swedish free schools had failed to transform pupils' academic achievement.
The biggest beneficiaries tended to be students from more highly educated families, Rebecca Allen of London University's Institute of Education found.
The report showed a "moderately positive" overall impact on performance when pupils are six and 15, but on more poorly educated families and immigrants the effect was "close to zero".