The FDA has called on the education secretary to publicly retract her comments that she would “probably have punched” Ofsted inspectors following an inspection of a school she had recently visited.
The union, which represents senior civil servants, said the comments have “damaged” the credibility and trust that stakeholders have in Ofsted.
During a Q&A event at the Association of School and College Leaders annual conference, Keegan said: "I had recently actually a fantastic school I went into and they told me how their Ofsted experience had gone. And I was shocked. I thought, 'God if I had met these people, I'd have probably punched them'."
She added: "They were really rude. You expect people to be rude when you're a politician, you kind of sign up for that, but when you're trying to run a school and educate children and change lives, you don't expect somebody to come in and not be respectful."
In a letter to Keegan, FDA general secretary Dave Penman said her comments "serve to further stoke division between inspectors and school leaders, adding to the existing difficult climate around school inspections”.
“Our focus is very much on ensuring that inspectors can carry out their duties safely and without fear," he added.
In June, Ofsted announced changes to improve inspection arrangements after headteacher Ruth Perry took her own life in January following an Ofsted inspection – with her sister saying she had described it as “the worst day” of her life.
Penman said the FDA would “welcome constructive, progressive and respectful discussions with yourself and others in government with a view to re-energising relationships between all parties concerned”.
FDA national officer for Ofsted Matt Newman told Schools Week last week that Keegan’s comments were “completely unacceptable”.
“Ofsted inspectors are hard-working, decent people who are passionate about what they do," he said. "For a minister to suggest that it is acceptable to assault inspectors is irresponsible and dangerous. It will only serve to undermine the credibility of the inspection process”.
The Department for Education declined to comment.