Image caption Churchill delivering his famous Iron Curtain speech in 1946

Winston Churchill coined the phrases "special relationship" and "Iron Curtain" on a lecture tour of American universities - and his words still resonate today, says historian David Cannadine.

In a few days' time, David Cameron will be journeying to Washington to visit Barack Obama, and according to a White House Statement, his visit will "highlight the fundamental importance of the US-UK special relationship and the depth of friendship between the American people and the people of the United Kingdom".

Perhaps it will, and I hope it does, but it's also likely to give rise to at least two challenging questions. Is America's relationship with Britain as special as it used to be? And is it genuinely more special than with any other country?

These matters have been much on my mind of late, because I've recently returned from lecturing at Westminster College, in Fulton, Missouri, where in March 1946, Winston Churchill gave one of his most significant post-war speeches in which he launched the phrase "special relationship" into popular currency.

Churchill was merely a private citizen, having been turned out of 10 Downing Street at the general election in the previous summer, but he was introduced by the American President Harry S Truman, and during the course of his speech, he offered a new and in many ways alarming view of the post-war world.

From Stettin in the Baltic to Trieste in the Adriatic, Churchill insisted, an Iron Curtain had descended across Europe, dividing the continent between a free and democratic west and a totalitarian and Communist east. The Iron Curtain was the first phrase his Fulton speech made famous, and the second was indeed the "special relationship" which he believed existed between Great Britain and the United States.

Churchill thought the Anglo-American connection was critical to maintaining the peace of the world in this new Cold War era, and we shall no doubt be receiving an update on its current state in the next few days.

Although it's a considerable distance from any major American city, Westminster College, Fulton is a remarkable place: in one guise, it's an energetic and innovative liberal arts college which draws its undergraduates from all over the US and from far beyond.

In another, it's become a shrine to Churchill and his Iron Curtain speech, and on its campus is a reconstructed London church, of St Mary the Virgin Aldermanbury, built by Sir Christopher Wren, in which I delivered my lecture, and which constitutes part of the National Churchill Museum.

Figure of speech Winston Churchill's speech to Westminster College, in Fulton, Missouri, on 5 March 1946, launched phrases such as the "special relationship" and the Iron Curtain. Read the full transcript of the speech

In yet a third guise, it's a place where the Cold War, to which Churchill had drawn such powerful and eloquent attention, was also pronounced to be over: both Ronald Reagan and Mikhail Gorbachev went to Fulton to say so in the early 1990s, and part of what had been the Berlin Wall is now on display on the college campus.

It's easy to regard Churchill's association with Westminster College as being almost incidental: such was his global fame after 1945 that he could have delivered his Iron Curtain speech virtually anywhere in the western world; and although he had been Chancellor of Bristol University since 1929, his connections with higher education or, indeed, with education of any kind, were never all that close.

He hadn't attended university, which was something he regretted all his life; although he retrospectively exaggerated his scholarly limitations, he'd never been a happy or particularly successful schoolboy at Harrow; and in many ways he later educated himself.

Yet in the years of his greatest fame, Churchill delivered several important speeches in American colleges and universities, in which he surveyed a broad landscape extending far beyond the confines of British public affairs, and offered more speculative and wide-ranging thoughts on the recent past and on how future events might unfold.

Churchill had given the first of these speeches at Harvard University in September 1943 where, at the behest of President Franklin Roosevelt, who was himself a Harvard graduate, the prime minister received an honorary degree.

The Americans and the British had been fighting side by side against Germany and Japan since Pearl Harbor, and Churchill took the opportunity to dwell on and embellish this collaboration in a speech on "Anglo-American Unity".

Image caption How special is the US-UK relationship now?

Both countries, he proclaimed, shared a common history, a common language and a common literature, and during the course of the 20th Century, they'd twice been on the same side in wars against tyranny and dictatorship and for liberty and freedom.

Surely, Churchill urged, this shared inheritance and these joint military endeavours must be the prelude to an even closer and more permanent association between the two great English-speaking democracies.

This was a theme to which Churchill had been attracted since the early 1930s, but Roosevelt was less enthused, for he saw the wartime alliance between the United States and the United Kingdom in a much more cold-hearted and calculating light, and the same would later be true of his successors in the White House, Harry S Truman and Dwight David Eisenhower.

Previously in the Magazine The "special relationship" with the US has haunted most occupants of 10 Downing Street, as they have striven to re-create what they believe was that earlier golden age of transatlantic friendship. ReadDavid Cannadine's article on the US-UK special relationshipfrom 2006

Also: President Obama hails 'special relationship' - May 2011

So while Churchill took every opportunity to urge the cause of Anglo-American friendship and collaboration, his ardent Atlanticism was never fully reciprocated in Washington, and the vision he had spelt out in his Harvard speech was never realised - except in the pages of his multi-volume History of the English-Speaking Peoples, on which he had begun work during the late 1930s, and which he eventually published 20 years later, after he'd finally retired as prime minister.

In addition to the speeches he delivered at Harvard University and at Westminster College, Churchill also gave an address at the Massachusetts Institute of Technology in March 1949. Once again, he was invited to share the podium with Harry Truman.

The president pulled out at the last minute, but Churchill delivered another wide-ranging survey, reflecting on world history during the last 50 years, to which he added some futuristic observations appropriate to the place where he was speaking.

While Churchill took every opportunity to urge the cause of Anglo-American friendship and collaboration, his ardent Atlanticism was never fully reciprocated in Washington

As at Harvard and Fulton, Churchill extolled the close connections between the United Kingdom and the US, and he reiterated his belief that Communist Russia represented a massive threat to freedom.

But he also drew attention to the growing importance of science and technology in the modern world. He spoke about aeroplanes and submarines and radar, and he began by lamenting that "we have suffered in Great Britain by the lack of colleges of university rank in which engineering and the allied subjects are taught".

Although he'd studied scarcely any science at school, Churchill was fascinated by weapons and gadgets and technology, which was why he had been so attracted in his youth to the novels of HG Wells, and why he later became a close friend of Professor Frederick Lindemann, Lord Cherwell, who was for many years his unofficial scientific adviser.

And the opening words of the speech he gave to the Massachusetts Institute of Technology contained the germ of an idea to which Churchill would return after he had ceased to be prime minister.

In retrospect, he came to regret that that he hadn't done more while in power to promote science, technology and engineering in Britain, and he continued to lament that there was no British equivalent to MIT.

Image caption Churchill wanted a British equivalent to the Massachusetts Institute of Technology (above)

Thus was born the idea of establishing a new college at Cambridge University which would be both the national memorial to Churchill himself, and also a forcing house for those scientists, engineers and technologists on whose brains, abilities and inventiveness the future of Britain was now deemed to depend.

The scheme to establish Churchill College, Cambridge, was duly launched in 1958, the first undergraduates were admitted three years later, and the appropriately modernistic buildings were completed in 1968. In accordance with Churchill's wishes and concerns, the statutes required that 70% of the undergraduates should be studying science or technology.

But the college has also become a monument to its originator in another way, for in 1974 the Churchill Archives Centre was opened, which has since become the greatest British repository for the papers of major 20th Century figures, including not only scientists and technologists, but also generals and civil servants - and politicians. Margaret Thatcher's papers are housed there, and so, too, are Churchill's own.

Having been originally conceived as an institution devoted to science and the future, Churchill College, Cambridge, is now at least as famous for history and the past. As a lover alike of technology and tradition, I wonder which version of his national memorial Churchill himself would have preferred?