Leslie Costar was born in South London and lives with his partner, Karol. Since 2001, he has run a successful joint business, balancing entrepreneurial life with a lifelong love of storytelling, history, and the written word.

In 2025, the ideas and inspirations that had been forming for years finally came together, leading him to begin writing his first novel, A Trinity of Lies.

When not writing, Leslie enjoys tea, theatre, books, and the company of animals — especially Reuben and Archie, their pet dog and cat respectively, whose expertly timed naps provided no shortage of inspiration.