For many years the story of Cromie has been overshadowed by histories of the greater tragedy found on the Western Front in World War I. Yet, like T E Lawrence, Cromie's individual exploits reveal a classic British hero: noble, tenacious and beloved by all who served under him. Churchill called him a man of exceptional gifts.

Cromie became a submarine commander at the remarkably young age of 24. By this time he had already seen action in the Boxer Rebellion, received the China Medal and had been mentioned in despatches. His compassion and care for his men gained him the Royal Humane Society's Bronze Medal, when he almost lost his life attempting to save a drowning sailor.

In 1915 he was chosen to head a flotilla of submarines to attack German shipping in the Baltic Sea. Here, he achieved great success despite the hazardous nature of the climate and the threat of the German navy. He was decorated three times by the Czarof Russia and received the DSO.

During his three years in the Baltic he became fluent in Russian. He only survived the difficulties of the Bolshevik Revolution in 1917 because of his consummate skills as a mediator and diplomat. His murder in the British Embassy in 1918 at the age of 37 remained a tragic mystery for many years – until now.

Bainton's extensive research has revealed why Cromie has previously been omitted from official histories of that difficult period. The circumstances surrounding his murder exposed facts about his complex character, his relationship with the Bolsheviks and the British Establishment - and importantly the story uncovers the duplicity of the allies as they struggled to formulate a reaction to the tidal wave of the Russian Revolution.