Amanda Foreman wrote the bestselling biography The Duchess, which inspired the new film starring Keira Knightley and Ralph Fiennes. The book, also known as Georgiana, Duchess of Devonshire, won the Whitbread prize for Best Biography in 1999.

Born in London in 1968, Foreman grew up in Los Angeles with an English mother and an American father, Carl Foreman, an Oscar-winning screenwriter whose films include High Noon.

Since publication of The Duchess, Foreman has worked as a presenter of TV and radio histories including Wellington’s Women on Channel 4. She also writes for newspapers and magazines.

Foreman lives between London and New York with her investment banker husband Jonathan and their children Helena, six, Theo, five, Halcyon, three, and twins Xanthe and Hero, 14 months.

How much money do you have in your wallet?

£200 and about $200. I bought sandwiches on the motorway on the way up to Chatsworth [the Devonshire family seat]. My husband and I drove up and decided it was the perfect place to spend time alone together.

Do you prefer cash or cards?

I am a card person. We pay off everything at the end of the month.

I am the worst person to talk to about money. I share one trait with Georgiana, which is that I try to hide bills under the desk or in the drawer or under the carpet if possible. We bank with HSBC, and my credit card is with them as well.

Are you a spender or a saver?

I veer between the two extremes — a kind of binge saver. I have recently spent a lot of money on books.

Often the books I consult are out of print and so I have a lot of antique publications hanging around. I usually look for them online at specialist websites.

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