The Secrets of Station X by Michael Smith

collateral information or even the reference books and maps wherewith to disentangle the obscurities of the German texts; few in the ministries could currently assess their significance in their disguised form, recipients in the operational theatre could only take them at their face value as agents’ reports; not many of them arrived in time for action to be taken; and even if all the material had been available and correctly appreciated, it is doubtful whether in the prevailing confusion, any practical use could have been made of it. Disguised and mutilated to resemble an agent’s report, it lost its integrity, did not inspire confidence and could not be correctly assessed.
    But in real terms the dismissive attitude of the military at this time to any intelligence produced by Bletchley Park was irrelevant during the Battle for France, which was already lost by the time Red was broken. The Allied troops were already in full retreat and even if they had accepted that the intelligence was accurate, they would have been in no position to make proper use of it. Nevertheless, vital lessons were learned allowing the system to be revised so that Ultra intelligence could have a direct effect on any future campaigns fought by British troops. It was clear to Menzies and the directors of intelligence in the Admiralty, War Office and Air Ministry that they had to find a way to get the Bletchley Park intelligence, now distinguishable by the classification Most Secret Ultra which appeared at the top and bottom of each sheet of the reports, to commanders in the field, with someone involved in the reporting process on the ground fully aware of where the information came from and its true value while at the same time protecting it and limiting knowledge of the fact that the British codebreakers were reading the Enigma messages.
    The issue was discussed at cabinet level and in mid-June 1940, the War Office set up a mobile Special Signal Unit, the role of which was to provide liaison with major commands so that Ultra intelligence from Hut 3 could be passed on direct. The unit was in fact run by Richard Gambier-Parry, head of Section VIII of MI6, and its original title of Special Signal Unit did not last long because the abbreviation SSU was assumed to be Secret Service Unit. The units were later split into two with Secret Communications Units attached to all major command posts to provide the communications links via which the Ultra intelligence would be passed and Special Liaison Units set up and controlled by Frederick Winterbotham, the head of the MI6 Air Section, alongside them passing the intelligence on to commanders.
    Although it would be a year before the SCUs and SLUs would play their real role, they were to be critical to the futureuse of Ultra intelligence by operational commanders. They were designed to provide the intelligence produced by the codebreakers swiftly and securely to commanders in the field. The SCUs were the communications experts linking the unit to the codebreaking centres, while the SLUs were made up of intelligence officers provided by MI6, who passed the Ultra material on to the commanders. Their role was to control the use of all high-grade signals intelligence, not just Enigma material, strictly to ensure that only those who had been indoctrinated knew of its existence. They also had to enforce the regulations on its use, making sure that it was never acted upon without a secondary source being available, to prevent any German suspicion that Enigma had been broken, and to liaise with the codebreakers on any queries from commanders.
    The SLU officer was responsible for personally delivering the Ultra message to the commander or to a member of his staff designated to receive it. All messages were to be recovered by the SLU officer as soon as they were read and understood. They were then destroyed. No Ultra recipient was allowed to transmit or repeat an Ultra signal. Any action taken by a commander on the