She is the revolutionary at the heart of education’s most traditional club: the first woman and first former state-school head to lead the most venerable society of boys’ private schools in 130 years.

But then Priscilla Chadwick, new chair of the Headmasters’ and Headmistresses’ Conference, has never been frightened of ruffling a few feathers. One of the proudest moments of her 35-year career was in the early 1990s when, as the head of Bishop Ramsey comprehensive, London, she tackled Michael Fallon, the former Tory education minister, over her appalling school buildings.

Mr Fallon had reluctantly accepted an invitation to tour the school after a series of angry letters from the head. The boys’ showers had been closed for two years because of an infestation of rats, the lower school had been evacuated after wiring was deemed unsafe and the gym was condemned and about to collapse.

“I was livid, I just couldn’t take it anymore, something had to be done,” says Dr Chadwick. “I was told that Michael Fallon would not be able to promise us any money but I just put him on the spot.”

The Government agreed to fund a complete pound;4.5 million refurbishment of the school. Today, sitting in the salubrious surroundings of the Pounds 12,000-a-year Berkhamsted Collegiate school, Hertfordshire, where she is principal, Dr Chadwick could not be further from the rat-plagued London state school.

Her arrival at Berkhamsted, whose old boys include Graham Greene (Greene’s father was a former head), coincided with one of the most controversial periods in its 461-year history as she was charged with merging the separate boys’ and girls’ schools.

Despite opposition from parents, within three years the prep school and sixth form were mixed, although boys and girls are still separate between the ages of 11 and 16. Dr Chadwick did away with the “ghastly green” girls’

uniform and introduced modern green, navy and black kilts. She rejected the title headmistress - “it is a horribly traditional public school title and was not really fitting in with the way the school was developing”, and became Berkhamsted’s first principal.

Cambridge-educated Dr Chadwick was dean of educational development at South Bank university for five years between her headships at Bishop Ramsey and Berkhamsted. She is a fellow of the Royal Society of Arts and chaired an advisory committee for the BBC on children’s television.

The organisation, which represents 240 heads of all-boys and mixed schools, only admitted its first woman member in 1994. It now has six women members in the UK. But how is the club, which lists Eton and Harrow among its most famous members, taking to having a woman at the helm?

“I have not experienced any animosity, and would not expect to,” she said.

“The fact that I am a former state-school head is, for me, more important than the gender issue. At a time when the two sectors are increasingly co-operating, I think my experience of both is quite invaluable.”

The Charities Bill, which will force private schools to prove their “public benefit”, is likely to be a main focus of her year, plus the possible merger of HMC and the Girls’ Schools Association (the timing, says Dr Chadwick, is nothing to do with her). She has rejected the Government’s proposal that private schools should sponsor academies, although she insists the relationship between HMC and No 10 has never been better.

“Compared to previous governments, this Labour administration sees the independent sector increasingly as a partner, rather than a competitor.

There is a lot we can share, although we will have to be careful to retain our independence - that is the message I will be carrying through throughout 2005.”

* graeme.paton@tes.co.uk