Thursday Book: Blunders behind enemy lines

BETWEEN SILK AND CYANIDE: THE CODING BATTLES OF WORLD WAR TWO BY LEO MARKS, HARPERCOLLINS, pounds 19.99

"BETWEEN SILK and cyanide" was the choice that confronted Special Operations Executive (SOE) operatives in the field. So the 22-year-old Leo Marks - creative cryptographer with SOE from 1942 to 1945 - told his boss. Either employ a series of ciphers printed on strips of silk, each one destroyed on use, or else the cyanide pill with which the underground agents in occupied Europe were issued to escape the tortures of the Gestapo.

Leo Marks never made it into the field himself. But his memoirs are as explosive as any sabotage conducted by those who did. Compulsive reading, they cover the Whitehall in-fighting between SOE, which was set up by Churchill in 1940 to "set Europe ablaze", and those rivals in the Foreign Office (FO) and MI6 who wanted to control, if not suppress it.

The history of this conflict has been told before but rarely, if ever, with the passion with which Marks addresses it. This is the passion of a man who was far from seeing the overall picture, but concerned that outside interference would increase the dangerous incompetence inherited from MI6, which imperilled the agents in the field. Marks found himself caught up in other bureaucratic battles, including one between de Gaulle's Free French and the Whitehall-American alliance, intent on excluding de Gaulle from the position of equal and respected ally on which he insisted. His sympathies, aroused by the legendary Wing-Commander Yeo-Thomas, lay towards the French.

Other themes in these memoirs are co-operation with the Norwegians, who planned to destroy the German supply of "heavy-water" and hence Hitler's prospects of making atomic weapons; and with the Danes, who successfully resisted a proposal from the FO and MI6 to exclude SOE from Denmark and Scandinavia. They also include the training and tragic careers of the agents Violette Szabo and Noor Anoyat Khan, alias Madeleine; the career and survival (through German capture) of Yeo-Thomas himself; and a brief encounter with the Lawrence Durrell-esque politics of SOE in Cairo.

The most explosive theme in this book, however, is its account of how Leo Marks battled for two years to convince his superiors that the entire SOE operation in the Netherlands, including the representative of the Dutch government in exile and the "secret Dutch underground army" on whose action at the time of D-Day so many hopes were pinned, had fallen completely under the control of German army intelligence. Arms, money, and a ceaseless string of SOE-trained Dutch agents were dropped into Holland, straight into the arms of German reception committees organised by Herr Ciskes, the commanding officer of the Abwehr in the Netherlands.

The agents so captured did their best to alert London, by following the procedures laid down to indicate that they were operating under enemy control. Their warnings, via deliberate mistakes, were ignored. Still worse, the separate operations were put in touch with each other - a complete breach of common-sense security. Every time London pressed for a named agent to return to London, he suffered an unfortunate accident. Yet the "old hands" blithely ignored everything.

Marks's suspicions were intensified by his realisation that, alone among SOE radio operators in German-occupied countries, those in the Netherlands never made a single mistake in transmission. But he was only 22, spoke no Dutch and had no field experience. Even when two of Giskes's victims escaped to Switzerland, the old hands saw this as German disinformation, and the escapees were held in prison.

Finally, on April Fool's Day 1944, Herr Giskes, realising that he had been rumbled, blew the gaff in an open message sent out through all the captured radio operators. The British began again, dropping agents blind to start afresh. Even then Giskes's men caught two of them. But, this time, their deliberate mistakes were read correctly in London.

Leo Marks never once loses contact with the personal courage and sufferings of the agents in the field, the reality which so shames the Whitehall warriors in the eyes of posterity. This fuels his sense of inadequacy, despite his achievements. He must be put in the category of backroom twentysomethings who did so much for British wartime intelligence; indeed, he belongs with Harry Hinsley, the guru of British scientific intelligence, who made the codebreaking operations at Bletchley Park acceptable to the top brass of the forces. His tale is by turns fiery, scabrous, infuriating and deeply tragic. The eyes mist over; the throat constricts; the heart thumps. I found Between Silk and Cyanide impossible to put down.