"GCHQ surveillance: Germany blasts UK over mass monitoring"

From The Guardian, 26 June 1943:

The German government has expressed the growing anger of its military chiefs over Britain's mass programme of monitoring radio traffic and directly challenged UK ministers over the whole basis of GCHQ's Bletchley Park surveillance operation.

The German Reichsinnenminister, Dr Wilhelm Frick, who has described the secret operation by Britain's eavesdropping agency as "a rather unsporting way of conducting warfare", warned UK ministers that evil totalitarian states could not flourish when enemy countries penetrated their "veil of secrecy".

Reichsaussenminister Joachim von Ribbentrop sent two letters on Tuesday to the British Home Secretary, Anthony Eden, stressing the widespread concern the disclosures have triggered among the German armed forces and demanding to know the extent to which their military operations have been compromised.

It is the first major challenge to Winston Churchill's coalition government to publicly justify its mass radio monitoring operation, which was revealed in documents leaked to the Soviets by GCHQ officer John Cairncross.

A spokesman for GCHQ refused to comment, pointing out that he was sworn to silence by the Official Secrets Act until 1975.