I arrived at the cavernous Washington DC apartment that Carol Blue shared with her husband, the late Christopher Hitchens, a couple of hours ago. Now I’m sitting, cross-legged, on the vast parquet floor. The thin winter twilight is fading and Blue is flicking through a shoebox-sized sheaf of black-and-white images – pictures that Annie Leibovitz, the doyenne of celebrity photographers, took, as a favour, when Blue and Hitchens married in 1991.

The fourth anniversary of his death had been the previous day, and Blue was due to mark it by travelling to New York for drinks with Martin Amis, the novelist best friend whom Hitchens once called “the only blond I have ever really loved”. But Blue says that a deadline kept her from attending