During a 1946 speech at Westminster College in Missouri, Churchill described the alliance between the two nations as the "special relationship" that required not only "the growing friendship and mutual understanding" but also the "continuance of the intimate relationship between our military advisers, leading to common study of potential dangers".
Security is still a cornerstone of the relationship, as are trade and less tangible things like shared language and the fact that many Americans are proud of their British roots.
Donald Trump's July visit to the UK will be his first as president of the United States.
The biggest protest will take place in central London on Friday when thousands are expected to take to the streets to join the "Stop Trump" march.
Mr Trump has recently been under fire for his immigration police which saw the separation of immigrant families and caused wide-spread anger.
"Several of the events are expected to attract large crowds and there will be road closures in connection with those events", the statement said. A giant inflatable depiction of Trump as a almost naked baby will hover above Parliament Square. The proposal was debated in parliament where Trump was heavily criticized.More news: Adult film star Stormy Daniels arrested at OH strip club, attorney says
The US Embassy in London has issued a warning to Americans in Britain to keep a "low profile" during Donald Trump's visit.
Trump was flying over after a fraught North Atlantic Treaty Organisation summit in Brussels where he piled pressure on allies to double their defence spending.
The US embassy in London warned Americans in the United Kingdom to keep a "low profile" and be aware of their surroundings as President Donald Trump visits in the coming days.
"You see the poor old Trump supporter is like a fella with a disease - he's afraid to put his hand up and say that he is a supporter", he said. "It's not for me to decide what's in good taste or bad taste". "We seem to be going into a cycle of rather regressive thinking". "Trump would share that level of national identity and patriotism".
Donald Trump has been under fire for his own immigration policy, which resulted in the separation of immigrant families.
About 50,000 people are planning to demonstrate in London alone on Friday, the day when Trump has meetings planned with both Prime Minister Theresa May and Queen Elizabeth II in the countryside.More news: ‘Catch and release’ immigration policy Trump abhorred is back in effect
They each have 4,000 square feet of floor space, including a Presidential suite with a large office and conference room, a medical suite that can be used as an operating room and two kitchen areas that can feed 100 people at a time.
"There is no stronger alliance than that of our special relationship with the U.S. and there will be no alliance more important in the years ahead", the British leader said.
"We need to ensure there is a balance between protection and public safety and the public's right to peacefully protest".
But that could change.
He then added: "The people voted to break it up so I would imagine that's what they would do, but maybe they're taking a different route - I don't know if that is what they voted for". "Britain is going to have to look right around the world for allies with which to do trade deals".
Unlike visits from previous presidents, he won't be spending much time in London after his arrival.More news: Donald Trump: 'Nato is much stronger than it was two days ago'
He will then travel to Helsinki for a summit with Russian president Vladimir Putin.
- The man with the world's longest fingernails finally had them cut
- Vertonghen 'gutted' after semi-final loss
- Oil rallies as IEA warns of output capacity limits
- Scientists Capture the Moment an Iceberg Breaks off from a Greenland Glacier
- LONDON FALLING: US Embassy Warns Americans of 'VIOLENT' PROTESTS During Trump Visit
- Senator Graham Slams Democratic Dissent of Kavanaugh
- Google updates Inbox app to be compatible with the iPhone X notch
- LA woman held for July 4 beating of elderly man
- Dejan Lovren Says He's One Of The Best Defenders In The World
- Marcus Rashford's heartfelt message to Gareth Southgate after England World Cup heartbreak