Winston Churchill coined the term “special relationship” in a 1946 speech in Fulton, Missouri. He said a unique bond between the United States and the United Kingdom was the “only means” by which the world could achieve its “full stature and strength” in the face of communism.

Churchill had established a deep friendship with President Franklin D. Roosevelt throughout World War II, with the two exchanging more than 2,000 telegrams and letters over the course of the war.

“The modern special relationship dates from the combined military relationship of WWII, when Britain … ran what amounted to a united command with the USA,” Tim Oliver, an associate at think tank LSE IDEAS, told CNBC in an email. “That military relationship, and one of trust, remains the heart of the special relationship.”

In 1946, the U.S. and the U.K. established the UKUSA Agreement, an arrangement that established an unprecedented level of intelligence sharing between the two nations. Oliver said intelligence sharing, nuclear weapons and special forces are pillars of the special relationship today.

“That is the core that survives — and is often protected — from the vagaries of wider relations, not least presidential and prime ministerial relations,” he said.

Source: cnbc
History shows the US-UK special relationship is increasingly one-sided