Shortly after Unlikely Warriors was published in 2012, my publishers, Aurum Press, passed me a letter they had received from a reader wishing to contact me. He claimed to have some interesting information – and papers – relating to one of the British volunteers mentioned in my book. When I heard about the nature of the documents and the identity of the volunteer, my interest was piqued, to put it mildly.

The name of the volunteer was Ronald Malcolm Lorraine Dunbar. As anyone who has read my book (or, in fact, any book on the British volunteers in the Spanish Civil War) will know, Malcolm Dunbar was the senior British ranking infantry officer in Spain. A middle-class, Cambridge-educated, homosexual aesthete, he could hardly have been a less typical volunteer. Yet, like a number of other intellectuals, in Spain he discovered a hitherto undiscovered talent for military life. Ranking only soldado (private) at the Battle of Jarama in February 1937, he rose quickly through the ranks, becoming Chief of Staff of the entire 15th International Brigade at the Battle of the Ebro in July 1938. Unfortunately, the shy, taciturn Dunbar never gave any interviews on his time in Spain and information on him has always been fairly scarce, despite his high rank and illustrious record.

Not much is known about his life after Spain, either. During the Second World War Dunbar served in the British Army, but never rose above the rank of Sergeant, adding fuel to claims that veterans of the Spanish war were being discriminated against. He later worked in the Labour Research Department until, in July 1963, having apparently removed all identification from his clothing, he walked into the sea at Milford-on-Sea, near Bournemouth. A clear case of suicide on the face of it, yet intriguingly, as Vincent Brome pointed out in Legions of Babel, his (now out of print) history of the International Brigades, the coroner declared an open verdict at the inquest, rather than declaring his death to have been suicide. This, and Dunbar’s alleged relationship with the Cambridge spy, Kim Philby, have led to persistent rumours of official cover-ups and Secret Service skulduggery.

Following his death, Malcolm Dunbar’s papers, including a number of photographs, were saved by a close friend, the ballet dancer, Thérèse Langfield, whose partner contacted me. In June 2016, I finally fulfilled his wishes, when I handed over the mass of material to the Bishopsgate Institute in London, where they will be available to all. It’s a fantastic collection and I recommend it to anyone interested in the British in Spain.

Malcolm Dunbar is the subject of one of a number of biographies I am writing for a forthcoming book. Watch this space for updates.