Mixed is no blessing insist girls' schools
This week, however, he came straight to the point as he described the setting for this week's Girls' Schools Association annual get-together as "the most bizarre conference venue I have ever visited".
Alton Towers, the Staffordshire theme park, with its roller coasters, themed hotels and costumed waiters, was miles away from the image usually associated with the country's elite private-sector girls schools.
"I can only commend you on your diplomacy," said Mr Miliband as he addressed the gathering of more than 200 headteachers. But, if the settings were strange, talking-points were rather more predictable.
Cynthia Hall, head of the School of St Helen and St Katharine, in Abingdon, and president of the GSA, used her keynote address to champion single-sex education.
Pointing to new figures, gleaned from 5,300 pupils in 104 GSA schools, she said girls were more likely to study physics, chemistry, maths or languages when taught in classes away from boys, who undermined their chances.
"It makes me mad when I hear heads of co-ed schools dismiss single-sex education," she said.
David Hart, general secretary of the National Association of Head Teachers, said such views were outdated propaganda.
But speaking at the conference, Mr Miliband threatened to spice things up by siding with the private school view. He said boys and girls could prosper by being taught separately for a few years and said the evidence for single-sex teaching in mixed schools was startling.
A soon-to-be-released Cambridge university study shows that 13 per cent more boys and 14 per cent more girls gained at least five A*-C grade GCSEs in languages and maths when taught apart, he said.
"When interviewed, some of the reasons that pupils gave for the improvement were that they felt more confident to participate in the lessons, there were fewer distractions and they didn't feel the need to show off," he added.
The Secondary Heads Association will now survey every secondary school to gauge levels of success when lessons are tailored to suit the separate needs of girls and boys.
The minister was later heckled when he suggested classroom discipline was better than it was five years ago.
And a few private heads made it clear they disliked the view, championed by Labour, of universities favouring state-school pupils. But, with Alton Towers' rides switched off for the winter, that was as hair-raising as this conference was going to get.