The Education Minister had recently been to a primary in Loanhead to focus on reading and the kids, curious as ever, wondered what she did, MacKay revealed.
"I'm the heidbummer of Scottish education," Liddell informed the weans in language they could understand.
Radio Five subsequently took a close interest in the definition of "heidbummer" and whether it was a good thing.
The "heidbummer" and Coatbridge lass admitted: "You should have seen the look on civil servants' faces. Ministers are not meant to behave like that."
MacKay invited the Penicuik audience to quiz the minister on the heads' qualification. The "heidbummer" broke the silence. "Everything's gone quiet. For a small fee I'll go round all the unruly classes," she offered Alan Waugh, the school's heidie.
Waugh summed up. "Sometimes I'm known as the 'heidbummer'. I wish all those leaving now a safe journey home and if you're not in a hurry, registered with the General Teaching Council and qualified in history, maths or computing, please stay behind."
The "heidbummer" had disqualified herself earlier. "I'm no educationist. I'm a mum," she declared.