The Secret History of MI6 - Keith Jeffery [44]
The quest for a perfect secret ink was a constant preoccupation for the Bureau. In June 1915 Walter Kirke noted in his diary that Cumming was ‘now making enquiries for invisible inks at the London University’. In October he ‘heard from C that the best invisible ink is semen’, which did not react to the main detection methods.16 Frank Stagg recalled that ‘all were anxious’ to obtain secret ink ‘which came from a natural source of supply’. He said that he would ‘never forget “C’s” delight when the Deputy Chief Censor, F. V. Worthington, came one day with the announcement that one of his staff had found out that “semen” would not react to iodine vapour, and told the old man that he had had to remove the discoverer from the office immediately as his colleagues were making life intolerable by accusations of masturbation’. ‘We thought’, wrote Stagg, ‘we had solved a great problem.’ But ‘our man in Copenhagen . . . evidently stocked it in a bottle – for his letters stank to high heaven and we had to tell him that a fresh operation was necessary for each letter’. One of Thomas Merton’s first discoveries after his appointment in June 1916 was the method of secret writing used by German agents, who soaked an article of clothing in the requisite chemicals from which the invisible ink could later be reconstituted. Merton also invented a secret-writing method for Cumming: ‘Write on glass or on any hard material with a silver point. The trace will be entirely invisible, but it can be made visible as follows. Make up two solutions A and B. A: Metol 5 grs, citric acid 5 grs, acetic acid 15 grs, water 100 cc. B: Silver nitrate 10 grs, water 100cc. Mix 10 parts of A with one part of B and with 100 parts of water. This is the developer. It can be used only for 10-20 minutes after mixing.’17
In one account of the wartime Bureau, a note by Merton’s name says ‘worked at secret inks, bombs, &c’, and it is clear that Cumming warmly encouraged scientific and technical research. It is clear, too, from Merton’s experience that this research was shared with MI5 for counter-intelligence work. On Christmas Eve 1914 and early in the New Year Cumming was discussing the recruitment of technicians and the possible establishment of a wireless school, though it seems not to have been for the use of agents as the technology was not yet sufficiently well advanced to allow this. But an important coding section was developed, both to ensure secure lines of communication with representatives abroad by telegraph and to work on deciphering enemy signals. In Head Office Cumming was always ready to try out new gadgets. In March 1915 he drove out to the Sterling Telephone Company in Dagenham, Essex, to inspect a new type of soundproof door. In July two officers came ‘to explain & try the Detectophone’, evidently a covert listening device. More prosaically (though no doubt useful for office work, and also demonstrating how private-sector business practices could be introduced), in December ‘Browning brought a Dictaphone & installed it’. In October 1918, knowing Cumming’s predilection for mechanical devices and perhaps concerned about his mobility, Sir William Wiseman, the head of station in New York, sent him a state-of-the-art motorised scooter manufactured by the Autoped Company of Long Island City.18
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Operations in the West
The expansion of Mansfield Cumming’s secret service operations initially developed out of his prewar networks in Belgium, the Netherlands and Denmark. But from almost the very beginning he contemplated wider deployments: in Scandinavia, Switzerland, Russia and further afield. Over the first year or so of the war, both on his own behalf and as instructed by the Admiralty and War Office Directorates of Intelligence, he organised networks in the Mediterranean and sent representatives to Spain, Italy, Egypt, the