The markets are down, the currency is all over the place and people have woken up in Britain confused and worried about what the future might hold for international relations.
And what does this mean for the special relationship? Don't forget, it was just a few months ago that British politicians debated whether they should ban Trump from visiting Britain after a petition gathered over half a million signatures.
David Cameron famously described Trump as "divisive, stupid and wrong". Boris Johnson declared: "The only reason I wouldn't go to some parts of New York is the real risk of meeting Donald Trump."
"I look forward to working with President-elect Donald Trump, building on these ties to ensure the security and prosperity of our nations in the years ahead," she said.
Politicians have been sharing their reactions this morning as the news came in.
Many are sad.
A devastating day. For women. For people of colour. For a tolerant society. But we must not mourn, we must organise like never before.— Caroline Lucas (@CarolineLucas) November 9, 2016
Words fail me. Gutted #USElection2016— Lucy Powell MP (@LucyMPowell) November 9, 2016
I'd usually try to console myself and say it's always darkest before the dawn, but the next four years are looking so grim. #Election2016— Alison Thewliss (@alisonthewliss) November 9, 2016
But some are jubilant.
Tory MP Philip Davies congratulates Trump for his ‘stunning election victory,’ says he looks forward to ‘very close UK and US relations’— Matt Dathan (@matt_dathan) November 9, 2016
Now we all pick ourselves up dust ourselves off and renew our campaign for a world that is rational moral & decent!— Barry Sheerman (@BarrySheerman) November 9, 2016
Some are concerned with trying to analyse the results.
White voters (especially men) unsurprisingly for Trump but a third of Latino men & a quarter of Latino women also voted for him pic.twitter.com/S3OIjwUVJK— Liz Kendall (@leicesterliz) November 9, 2016
Pollsters, media commentators & most of all left of centre politicians need to ask "why do we so misunderstand our voters?" #ElectionNight— James Cleverly (@JamesCleverly) November 9, 2016
Some, including the former shadow leader of the House, Chris Bryant, and former Ukip donor Arron Banks, are getting into spats...
You and I have very different understandings of Christianity https://t.co/oBPThx7wi8— Chris Bryant (@RhonddaBryant) November 9, 2016
Many are worried, including Labour leadership candidate, Owen Smith.
A racist in The Whitehouse & a human rights abuser in The Kremlin. Time for us to leave Europe, or time to try and lead it & rebuild hope?— Owen Smith (@OwenSmith_MP) November 9, 2016
The world has become more dangerous this morning. Moderates across the political spectrum must calmly & firmly stand by our principles— Bob Neill (@neill_bob) November 9, 2016
That's it, America has chosen a different path & we wake up to a different world— Sarah Wollaston (@sarahwollaston) November 9, 2016
Some are plain confused.
Can't deny days like these make you question humanity. As voters chose to have a racist, sexist, xenophobe in the White House. I mean why?!— Chris Elmore MP (@CPJElmore) November 9, 2016
America... REALLY? #TRUMP— Owen Thompson (@OwenThompson) November 9, 2016
Lots are shocked.
NO NO NO NO NO !!!!!— Nadine Dorries (@NadineDorries) November 9, 2016
President Trump, a terrifying day for the world and for everyone who values democracy and freedom— Steve Reed (@SteveReedMP) November 9, 2016
Others are fed up.
Proof that in the right circumstances a pig's bladder on a stick can be elected as leader of the so called free World— Kevin Brennan MP (@KevinBrennanMP) November 9, 2016
But lots are gearing up for a fight.
Decent left of centre politics defeated by divisive right wing populism. Repercussions will be felt around the world incl here. Get ready.— Dan Jarvis (@DanJarvisMP) November 9, 2016
Fell asleep. But the nightmare was real. So much more now to do for our country, our planet and all humanity.— Luciana Berger (@lucianaberger) November 9, 2016
If you have woken up today feeling lost, heartbroken and helpless: Don't mourn, organise. Don't give up. They want you to give up. Don't.— David Lammy (@DavidLammy) November 9, 2016
2/2 There are many reasons for the defeat -junking our values & beliefs is not the answer. Getting globalisation to work for all is the task— Chuka Umunna (@ChukaUmunna) November 9, 2016
For those with a progressive heart. Our distress today is no reason to give up. No reason to leave the fight. It's the reason to join it ❤️— Alison McGovern (@Alison_McGovern) November 9, 2016
Those of us who believe in liberal, progressive and tolerant values ain't going anywhere. We must redouble efforts to make our case. https://t.co/PfwJbF0GpE— Stewart McDonald MP (@StewartMcDonald) November 9, 2016
US election: What you need to know