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Interception of enemy communications has always been a fruitful source of information about plans and resources. The widespread use of radio by all services, and the consequent ability to intercept enemy signals at long distances, led to the formation of Special Wireless Groups located at strategic points with the task of monitoring the signal networks of enemy and potential enemy formations and units. First formed in the 1930s, the 'Y' Service, as it is generally known, became a major intelligence resource in the Second World War.
 The most highly skilled tradesmen in Royal Signals were 'Special Operators' expert Morse operators and linguists. Their work, and of their colleagues in the RAF and Navy, contributed signal intelligence (SIGINT) to commanders in every theatre of war. Much of the material intercepted, however, was in cypher, and so was useless without the cryptographic analysts who were able to break the ciphers. The analysts were based at Bletchley Park, near London, and among their greatest achievements, the best kept secret of the war, was breaking the German 'Enigma' cypher machine. This machine, one of which fell into British hands in 1939, was employed throughout the war by all German forces to encrypt their most secret signals. Breaking the Enigma signals and the distribution of the resultant intelligence was code-named ULTRA.
The envelope date stamp marks the 50th anniversary of the Battle of the Ardennes (popularly known as The Battle of the Bulge') which took place from 16 December 1944 to 25 January 1945. Field Marshal von Undstedt was ordered by Hitler to recapture Liege on the Meuse and drive northwards to Antwerp, with the aim of splitting the Allied Command in two. The attack began on 16 December against the US VIII Corps, led by the newly formed German 6th Panzer Army. The attack took the allies by surprise, and made rapid progress towards the west in the first days. Afterwards there was much heart searching for the reason why ULTRA had apparently not given adequate warning. This is partly explained by the very tight Security in the German forces preparing for the attack, with units operating under wireless silence; but it also seems clear that the allied staffs (perhaps due to a degree of complacency) had not interpreted correctly the ample SIGINT available to them, which should have warned them.
It took much hard fighting, with many thousands of allied casualties, before the German offensive was repulsed and the position restored. SIGINT played an important part in helping the allies in the course of the battle.
The envelope design shows the formation sign of the US 101st Airborne Division which played an heroic part in the defence of Bastogne, besieged by the Germans until relieved on 26 December. Also shown is the sign of the British XXX Corps which with the US VII Corps led the counter attack on the northern flank of the salient. The date stamp incorporates the 'flaming sword' of General Eisenhower's Allied Command HQ. |
