London - When British Prime Minister Theresa May became the first world leader to visit Donald Trump at the White House in January 2017, it appeared the historic friendship between the two nations was in good health.

But a series of spats have driven the two leaders apart, creating tensions between the two leaders ahead of Trump's recent four-day visit to Britain.

Here is a chronology of their deteriorating relationship:

- 'No vacancy' -

November 2016: The US President-elect catches May offguard when he tweets that former UKIP leader and Brexit champion Nigel Farage "would do a great job" as Britain's ambassador to the United States.

May's Downing Street office is forced to say there is "no vacancy".

- Holding hands -

January 2017: May meets Trump at the White House, where he predicts that "great days lie ahead for our two peoples and our two countries," raising hopes of a swift post-Brexit trade deal.

The defining image of the trip is of Trump holding May's hand as they walk outside the White House, which attracted derision in Britain. The British leader invites her counterpart for a state visit.

But the feelgood factor lasts only a matter of hours, as the US leader unexpectedly announces a travel ban from seven Muslim-majority countries, affecting dual British citizens and wrong-footing British officials.

May says she "did not agree" with the ban, and MPs demand that she rescinds the state visit invitation.

- 'We're not schoolchildren' -

June 2017: Following previous rows, Trump again targets London mayor Sadiq Khan following a terror attack in the British capital.

Picking on a message from Khan telling Londoners there was "no reason to be alarmed" by an increased police presence, Trump tweets: "At least 7 dead and 48 wounded in terror attack and Mayor of London says there is 'no reason to be alarmed!'"

Khan responds saying: "We're not schoolchildren. He's the president of the United States, so I'm unclear what his beef is with me."

- 'Must be proactive -

September 2017: Trump weighs in on another attempted attack, tweeting: "Another attack in London by a loser terrorist. These are sick and demented people who were in the sights of Scotland Yard. Must be proactive!"

May responds it was "unhelpful" to speculate on an ongoing investigation.

- 'Wrong' to retweet far-right -

November 2017: Trump retweets three videos originally posted by Jayda Fransen, deputy head of far-right group Britain First, purportedly showing Muslims engaging in acts of violence, although one of the videos was later debunked.

May says Trump was "wrong" to retweet the messages, but the US leader hits back, tweeting to May: "Don't focus on me, focus on the destructive Radical Islamic Terrorism that is taking place within the United Kingdom."

- 'Bad deal' -

January 2018: Trump says he is not coming to inaugurate the new US embassy building with a tweet, calling its new site in south London an "off location".

"I am not a big fan of the Obama Administration having sold perhaps the best located and finest embassy in London for 'peanuts'", he wrote, adding: "Bad deal. Wanted me to cut ribbon-NO!".

Ravi Govindia, head of the council where the new embassy is located, said he would expect Trump to be familiar with seeking out a business opportunity to move into an up-and-coming neighbourhood.

"Our relationship is with the workers, the people and government of the US which is bigger and greater than any single administration," he told AFP.

- London 'war zone' -

May 2018: Trump tells a National Rifle Association convention that a "once very prestigious hospital" in London was like a "war zone" because of knife crime.

"Yes, that's right, they don't have guns, they have knives and instead there's blood all over the floors of this hospital. They say it's as bad as a military war zone hospital."

He then mimicked someone using a knife.

Knife-related crimes rose by 23 percent in London last year.

Professor Karim Brohi, trauma surgeon at The Royal London Hospital, said it was "ridiculous" to suggest guns are part of the solution to knife violence.

- Trump downplays attack on Brexit strategy -

By Dario Thuburn