School visits and activities that depend on any outside help have been put in doubt following a ruling by Wales's special educational needs tribunal.
It has ordered Llanidloes primary school, Powys, to give "external suppliers" -from parents involved in reading sessions to swimming-pool lifeguards -written, rather than verbal, information about individual children's special needs.
Headteacher Sue Parsons, who said the ruling was very difficult to implement because it contravenes the Data Protection Act, has temporarily suspended all such activities. The legally binding ruling was made after a hearing on January 12, when the tribunal found that a pupil with special needs was discriminated against while taking part in a sailing lesson in June 2004.
It comes as the education and lifelong learning minister Jane Davidson is encouraging schools to enhance the curriculum with activities led by external staff to give teachers more non-contact time.
Mrs Parsons said the school prided itself on the breadth of its curriculum and was saddened by the suspension of activities while a solution is sought.
The ruling is particularly significant for Llanidloes because 100 of its 385 children are on the SEN register and it uses some 300 external suppliers, including parents, members of the clergy, referees and staff at historical sites.
"We're faced with a situation that is going to affect every school in Britain," said Mrs Parsons. "I think it's a landmark case."
Powys county council is now trying to establish how the ruling will affect its other schools.
Spokesman John Evans said: "We are looking at the tribunal's notes to see if this situation is true for other schools. We are also meeting with Llanidloes to make sure the school has the appropriate policies and procedures in place to ensure it doesn't fall into difficulties again."
Mrs Parsons said the school had complied with the county council's regulations by verbally informing the sailing instructor of the child's special needs.
But the tribunal now wants the school to devise a written policy by September that ensures, "pertinent information concerning individual children with disabilities and special educational needs is provided in writing to the relevant suppliers".
It has told the school to seek legal advice on how to dovetail the provisions of the Disability Discrimination Act and the Data Protection Act.
Mrs Parsons added: "We must now clarify how much SEN information is required in writing and how to avoid contravening the Data Protection Act."
Parent Adrian Roberts, who has two children at the school and works at an outdoor activities centre, said: "This ruling is totally unworkable and has left nearly 400 children without after-school clubs. They are not getting access to anything parents are involved in and they are not getting trips.
"But if it applies to this school it applies to every school in Wales because it's legally binding."
The SEN tribunal, which was established in April 2003 to hear claims brought under the Disability Discrimination Act, said it did not comment on individual cases.
The Assembly government also declined to comment on the case, but stressed that disability discrimination legislation should not affect school activities.
A spokesperson said: "Schools have known since July 2002, when the Disability Rights Commission guidance was issued, that they needed to anticipate the needs of disabled learners and not simply respond to those needs as they happened.
"So these requirements are not unexpected. We would not expect them to affect the ability of schools to take pupils on school trips."
Mick Bates, Lib Dem Assembly member, said: "There needs to be a central government-sponsored body that deals with the legal side of school visits, because the pressure on schools is far too great to write up legal documents to avoid litigation that might occur.
"The government has the responsibility to reduce anxiety and provide central advice."
Referring to the Llanidloes case, he added: "Most schools have pupils with special needs and this position needs to be clarified."