Diary sheds new light on UK spy relationship with US
A diary which details how a crucial spy agreement was made between the UK and the US has been released by GCHQ in Cheltenham.
The documents were shared to mark the 75th anniversary of the UKUSA agreement made between intelligence agencies in 1946.
They detail the war time meetings which began at Bletchley Park and led to the secret agreement being signed.
The diary belonged to Alastair Denniston, former head of Bletchley Park. In February 1941, he wrote "The Ys are coming!" - meaning the 'Yanks'.
Denniston was referring to a group of American code-breakers at a time when the US had not yet entered the Second World War.
"There are going to be four Americans who are coming to see me at 12 o'clock tonight." he told his assistant. "I require you to come in with the sherry. You are not to tell anybody who they are or what they will be doing."
It was the start of a crucial relationship which saw the two sides sharing vital information throughout World War Two - including when Bletchley Park cracked the Enigma code.
Later entries in the diary reveal how Denniston and the now famous code breaker Alan Turing would travel to the US to meet with agents.
But it wasn't until after the war the relationship became more formal, when the UKUSA agreement was officially signed in March 1946.
The following decade saw the agreement grow to include agencies in Australia, Canada and New Zealand, and later became known as the Five Eyes.
In a joint statement Director GCHQ Jeremy Fleming and the Director of the US National Security Agency General Paul Nakasone said: "This alliance defines how we share communication, translation, analysis, and code breaking information, and has helped protect our countries and allies for decades. The amazing women and men at our two agencies use their skills and diversity to make a difference.
"For 75 years, this extraordinary partnership has enabled us to evolve and learn from each other. It helps us equip our leaders with the information they need. And it ultimately makes the UK and US safer. We celebrate those 75 years and we look forward to the future together."
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