Schools are at risk of legal action from disgruntled job applicants because of new laws designed to prevent discrimination against ill or disabled people, headteachers have warned.
The Association of School and College Leaders (ASCL) is concerned that the Equality Act has created a legal "grey area" that could mean heads who ask about applicants' previous attendance records - or ask them to fill in medical questionnaires - are accused of discrimination.
The ASCL says members are torn between legal requirements to ensure potential staff are "fit to teach" and the law that prevents schools from probing medical and attendance histories prior to a job offer.
Legal experts at the ASCL say that the equalities legislation - which came into force in October - was "rushed through" without proper scrutiny from employers and other groups.
Richard Bird, the union's legal consultant, said heads preferred to be able to appoint people who were fit to work rather than having to go through complicated capability proceedings further down the line.
But he added that, despite the view of some other lawyers, it would be "highly imprudent" of heads to enquire about a teacher's absence, either before or after a job offer. He said asking applicants and those who had received job offers to fill in medical questionnaires was "legally highly dubious".
Any heads who continue to use health questionnaires - and decide not to appoint on the basis of that information - could face legal action, Mr Bird warned.
School leaders have hit out against the rules, claiming they will not be able to filter out staff likely to take large periods of time off work.
Joan McVittie, head of Woodside High School in north London, said she always asked about attendance records, with a medical questionnaire sent to people who had received a job offer.
"The last thing you want to do is employ someone who won't be in front of a class," she said. "You wouldn't want someone teaching your children who was off every other day. Obviously if someone had a block of time off with cancer of something you would have to make a judgment, but you have to have this information."
The ASCL has asked the Department for Education for clarification on the issue. A spokesman for the DfE said new guidance on the "fitness to teach" rules would be released in the new year to ensure they align with the Equality Act.
"We will make clear that employers of teachers should no longer ask generic 'all-encompassing' health questions, but can continue to ask necessary, targeted and relevant questions which are designed to ensure a person can fulfil the requirements of the role applied for," he said.
This should "make the legislative requirements clear and minimise bureaucracy for schools", the spokesman added.