In 1992 Dame Stella Rimington became Director-General of MI5 - the first female Director-General, and the first to be publicly named.
Since retiring from the service she's forged a successful second career as a novelist, drawing on her MI5 experience to create the compelling Liz Carlyle series. The ninth book will be published in summer 2016.
In Alderney recently for the second Alderney Literary Festival, she spoke to us about her two careers, and why they're actually more similar than you might think.