* Fiona S is the tall fit one who works out regularly on her cross trainer. Fiona B is shorter, blonder and, er, plumper. She talks the talk about exercising but rarely gets round to it
* Fiona S takes taxis. Fiona B takes the bus
* Fiona B has 4 grown-up children and step-children. (Well grown-up in theory, anyway.) Fiona S sensibly doesn’t
* Fiona S is a party girl who hangs out with chefs. Fiona B hangs out on Twitter
* Fiona B is more tech savvy. She has two websites and a blog The Frugal Cook, Fiona S is not frugal. You should see her wardrobe.
* Fiona B lives in Bristol and has a house in the Languedoc in the south of France. Fiona S lives in London and a house in the Isle of Wight where she attends the annual rock festival
* Fiona S has a Britannia. Fiona B has an AGA.
* Fiona B has a weakness for chick flicks - and French nouvelle vague. Fiona S likes a dance
Other similarities: Both Fionas are convent-educated - and you know what that means . . . Both hate funfairs and crystallised ginger. And - get this - both married their husbands without telling their families and celebrated with lunch at the same restaurant, Bibendum. In the same month, October, but mercifully not the same year which would have been too spooky for words.