Born in 1946, Alan Judd served in the Army and worked in the Foreign Office before becoming a writer full-time. He draws on his military and diplomatic experience for his work, which includes the Charles Thoroughgood series of spy novels, following the protagonist through his experiences in the Army and the Cold War era intelligence service. Judd is also a biographer, with his subjects including MI6 founder Mansfield Cumming.

His latest novel, No 1 St James’s Park, is the second in his new Emily Grey series, centring on a Cambridge graduate recruited by a fledgling MI6 during the First World War.

So which are the spy novels Judd holds in greatest esteem? Here, he shares the five classic spy stories that have shaped the genre – and his own reading – the most.

The Secret Agent by Joseph Conrad

“Inspired by an 1894 anarchist bombing, Joseph Conrad’s novel endows the early spy genre with the introspection and moral equivocation found in more mainstream literary novels.