A plan to let secondary pupils across Europe spend up to a year at school abroad is being opposed by British officials because of stringent UK child protection requirements.
The European Commission (EC) hopes to start the scheme within a year and sees it as the secondary school equivalent to the popular Erasmus universities programme.
The scheme has already been trialled in 10 other EU countries, with 288 14 to 18-year-olds staying with host families in 2007-08.
But UK and Irish officials have said the scheme would be "utterly impractical" for their countries given the child protection checks that would be necessary.
Schools in Britain have already encountered difficulties arranging even short-term exchanges because of the need to carry out criminal record checks on all adults involved.
UK and Irish officials also fear their schools could be inundated with demand for visits.
The British Council is prepared to oversee the project in the UK if it proceeds. But Simon Williams, director of lifelong learning, said that other challenges included arranging visits that would not affect British pupils' exam preparations, and finding enough host families.
"Traditional exchanges involve a lot of paperwork, but hosting a child for a year would be much more onerous and intrusive," he said.
More than 1,000 UK schools have already established close ties with European counterparts through the EC's Comenius school partnership programme.
Jan Figel, the EU commissioner responsible for education, this week said he hoped to launch the Comenius "individual pupil mobility" scheme within 12 months.
"At university level, we have the famous, successful programme - Erasmus," he said. "We would like to get that at secondary level."
Asked about the child protection concerns, he told The TES: "There are some - I would even say many - obstacles. But as we have succeeded in the university community, I'm sure that we can address these."
Representatives from education ministries, including the UK's Department for Children, Schools and Families, will meet next month to thrash out the details of the scheme.
Nine out of 10 teenagers on the pilot project said they had been highly satisfied by the experience.
Wenke, a 15-year-old German, spent six months at a school in France. "Some of my German friends told me they would be scared to go abroad for such a long time. But for me this was a great experience," she said.
Adam Pokorny, head of Comenius's school education unit, said a Finnish colleague had been astonished at how French pupils had conversed in Finnish after only a few months in the country.
A Department for Children, Families and Schools spokesman said: "The safety of our children remains our primary concern, so any scheme that is brought in will need to satisfy the child protection safeguards that are introduced here."
Bonjour, Europe, pages 30-31.