"You are personally more popular than your policies entitle you to be, " she was told by the annual conference of the Secondary Heads Association in Torquay.
"We believe that the indiscriminate extension of selection by individual schools is educationally counterproductive, organisationally chaotic and morally dubious," said Bruce Douglas, the association's vice-president as he replied to Mrs Shephard's address.
"The return of the secondary modern school is not the gift that we as educators wish to bequeath to the next generation."
He also told her, however, that she carried "the genuine best wishes" of the association which, privately, feels its views have carried more weight in the Department for Education and Employment than with the Labour party's education team.
In a low-key speech, interpreted by most delegates as valedictory in tone, a relaxed Mrs Shephard thanked the association for its "invaluable" help and advice, before hurrying away to her Norfolk constituency.
The SHA, she said, had made a particular impact with its proposals on 14-19 education, on training for headteachers, and on discipline. "I have very much valued the close working relationship that we have developed over that time," she said.
She outlined some of the Conservatives' manifesto promises. Locally maintained schools, she said, would control 100 per cent of their budgets.
They would also control their own admissions, employ their own staff and own their own assets.
"Experience has shown that giving schools this greater degree of independence releases new energies, and enables schools to build on their strengths and drives up standards," she said.
Mrs Shephard defended the Conservative proposals for greater academic selection.
"We have not spent the past 18 years encouraging more variety and diversity in the schools system only now to wish a return to a two-tier system or a system with only one kind of school.
"But the important thing is that structural change will be at the wish of local communities and their schools."