It was a proposal which achieved the extraordinary feat of uniting four parliamentary select committees, five teaching unions, the Children’s commissioner, the Chief Medical Officer, the Association of Police and Crime Commissioners, two royal societies and no less than six medical royal colleges.

But yesterday the Education Secretary Nicky Morgan ruled out making sex education compulsory for all schools. This was a very strange decision, not just because so many wise and knowledgable people wanted mandatory sex education, but also because Mrs Morgan herself did.

In fact I can reveal she waged a valiant battle to persuade the Prime Minister to back her – but to no avail. What's worse is David Cameron decided to ignore the entreaties not only of his Education Secretary – and the aforementioned assembled ranks of supporters and experts – but also several other senior women in the Cabinet.