"I thought, 'Hallelujah, we've got a loony here'. At the end I said, 'Can I take your name again?'" remembers Katherine Eckersley (above left). So began a four-year friendship that has resulted in Ms Eckersley's name - and that of Virginia Frayer, former head of the Angel school in Islington - appearing on the dedication page of Jilly Cooper's exuberant and moving novel, Wicked!
Jilly Cooper visited Village high several times, and much of the school is mirrored in the fictional world of Larkminster comprehensive school - "Larks", in Jilly-speak. What the best-selling author witnessed in Derby was a team of committed staff giving an "educational year of their lives"
to a group of deprived, hitherto disaffected teenagers. So too at Larks there are children in care, children in trouble with the police and a head determined to help them succeed. (Larks's teachers, it must be said, are a more motley crew.) So, does Katherine Eckersley recognise herself in Janna Curtis, the feisty, red-haired head of Larks, given to messy love affairs and drinking "teacher's lemonade" - vodka and Fanta - at school functions?
"I never cried," says Ms Eckersley, firmly. "This woman seems to dissolve into tears at the drop of a hat."
Jilly Cooper became a bit of a heroine at Village high. She got the teenagers on side, not just by paying for a trip to Alton Towers, but by being interested in them. "The kids loved her," says Ms Eckersley. "She talked to them. She made them feel valued. But I think she was shocked by things she saw and heard. I think they touched her quite dramatically."
Despite initial suspicion, staff were won over too. 'She just charmed all of them," says Ms Eckersley. "In the end there was nothing they wouldn't do for her, even the most leftwing of my staff."
Gill Pyatt, head of Barnwood Park girls' school in Gloucester, is another headteacher who helped Jilly Cooper research her book. (True to Jilly-form, her list of affectionate credits covers eight pages, including thanks to her own adopted children's teachers in the independent sector.) Ms Pyatt (above right, with Jilly) briefed the author on everything from school budgets to how local authorities relate to schools, and GCSE exams in English literature.
In Gloucester, life imitated art as Barnwood Park was threatened with closure soon after Jilly Cooper began visiting. "She certainly managed to make sure our case, the injustice of our case, was known," says Gill Pyatt.
"She came to all the public events and kept saying it was a wonderful school. She would ring up the Times or the Telegraph or whoever." Jilly Cooper sat beside a nervous Ms Pyatt at public meetings. The head remembers the author holding her hand - literally - and saying, "You'll be all right, darling".
Does Gill Pyatt recognise herself in Janna Curtis? "I haven't got ginger hair," she says. "But I do lose it sometimes."
Jilly Cooper has established an annual prize for literature at Barnwood Park, which was saved at the 11th hour and was later declared the fourth most improved school in the country. When she came to the school in June last year to give out prizes, Jilly Cooper had one of her own for Gill Pyatt. It was the author's cardboard placard, reading "Save Barnwood Park", which she had brandished at meetings - with "Save" changed to "Saved" - wrapped up in purple paper, tied with bows.
"We love her," says Gill Pyatt. "She's so kind. And so sensible, really."