Writing in this week's edition of the Times Higher Education Supplement, she says: "To condemn comprehensive schools on purely academic grounds seems `elitist', and no accusation is more damning.
"Both left and right, for different reasons, are compelled to avoid such a charge, for the penalty of elitism is that all one's arguments are automatically disregarded."
But the former Mistress of Girton College, Cambridge, then adds the frank admission: "It was fear of the charge of elitism that led many members of the House of Lords, including myself, to sit by in cowardly silence when the title of university was bestowed on all the polytechnics, indiscriminately."
Lady Warnock, who chaired official inquiries into special education, and human embryology, makes her confession in a review of the book, We Should Know Better: Solving the Education Crisis, by the Conservative MP George Walden.
"It was the elitist charge," she says in a direct reference to the book, "compounded by that of hypocrisy, that was the undoing of Harriet Harman, whose case Walden calls `Labour's Dreyfus Case', transcending as it did the individual, and taking on a symbolic role within the party."
The thesis of Mr Walden's book is that the co-existence of the private and state school systems needs to be tackled if overall education is to be improved.
Provocatively, Lady Warnock - a former headmistress of Oxford High School - says: "For one thing, consciousness of belonging to the inferior part infects teachers in maintained schools, however much they prefer, on missionary or political grounds, to teach there.
"Hence, they allow themselves to be represented, as many as 200,000 of them, by the National Union of Teachers, a union that is of the old-fashioned militant left, deeply anti-academic, seen by the outside world, indeed, as deeply stupid. Public and parliamentary respect for teachers as a profession is therefore non-existent."
Arguing that the use of market forces had not succeeded in improving schools, Lady Warnock says: "Any method of improving education, once one has passed beyond routine abuse of teachers or pious hope, will inevitably be expensive.
"Yet it has to be faced that unless this money is spent, Britain will fall further and further behind, until it reaches the lowly status of an underdeveloped country."
She adds that the word, "developing" would be too optimistic a term to use in that context.
Aligning herself with Mr Walden, she says that the greatest hope for an improvement in education standards lies in selection. "This old-fashioned, once-obvious truth is beginning to be recognised by both political parties."
Mr Walden, she says, speaks of the "nightmare of the right", of A-level standards eroding and degree courses becoming no better than extended sixth-form sessions. "I can assure him," she adds, "that here and there, but increasingly, the nightmare is reality."Reuse content