She is, as you might expect of a woman who now represents more than 200 leading independent girls' schools, unimpressed by Professor Tim Brighouse's idea that parents who choose private education for their children should pay higher university fees.
"I think it's a rather glib argument," she said."There are lots of parents who can barely afford the fees, some take out second mortgages and all contribute to other children's education through their taxes."
Nevertheless, Mrs Hall, 51, is committed to extending partnerships between state and GSA schools, which she has championed at her own school, St Helen and St Katharine in Abingdon, Oxfordshire.
At a time when a growing number of independent boys' schools are turning co-educational, Mrs Hall remains firmly convinced of the value of single-sex teaching - especially between the ages of 11 and 16.
"I think there is a subtler battle now to be fought with girls," she said.
"Girls do very well, they are getting good results, but they often do well in order to please people around them.
"There is a lot of work we can do with girls to help them to work out their own reasons for doing what they want to do in education."
Mrs Hall has spent a good deal of her time in single-sex surroundings, though until the age of seven the single sex was male. Her father, Robin Davis, was deputy head of the all-boys Merchant Taylors' school in Northwood and the family lived in a school house.
She attended the highly academic all-girls North London Collegiate school, before winning a place to the then-all-women St Anne's college, Oxford.
There she edited the Oxford student newspaper Isis with Sally Emerson, a writer who is married to former Times editor Sir Peter Stothard. Her own husband is Tony Hall, the BBC's former head of news, now chief executive of the Royal Opera House.
From 1978 to 1990 she taught English at St Paul's girls' school in west London. After a break from teaching, in 1993 she became head of St Helen and St Katharine, which was was named the Sunday Times independent school of the year in 2000 and was placed among the top five schools in last summer's GCSE tables.