But the MP (right), who has been under pressure to justify the spiralling cost of the Olympics, had not counted on Patrick Moran, a local schoolboy invited on to the stage to interview her.
"Would the money spent on the Olympics be better spent on education?" he asked, to laughter from an audience of teachers.
Ms Jowell prevaricated in typical politician style, bandying about the regeneration buzzword.
But young Patrick would not be fobbed off. With all the panache of Radio 4's John Humphrys, he asked again: "So you don't think the money would be better spent on education?"
After laughter died down, one delegate said: "He completely had her. It was great for the audience of teachers to watch her squirm."
Later a schoolgirl had the chance to interview Fergus Balfour, managing director of Birdseye. She asked if his company would ever bring out a range of fresh foods, given that they are much healthier. "No," he replied. "We believe frozen is the new fresh." His young interrogator did not look convinced.