Loved and loathed: political leaders divided over new Prime Minister-in-waiting Boris Johnson
As Boris Johnson secured victory in the Tory leadership race, reaction from the political world veered between delight, dismay and derision.
Defeated hopeful Jeremy Hunt led a host of his fellow Conservatives in congratulating Mr Johnson after a "well-fought" campaign.
"You'll be a great PM for our country at this critical moment," he tweeted.
Many leading Tories, including a number who may now be hoping for key Cabinet positions, repeated calls for the party to unite and ensure the UK's departure from the EU.
Among them were other former leadership contenders including Matt Hancock, who tweeted: "Huge congrats to Boris Johnson on winning the Conservative leadership.
"Time for us to get behind him to deliver Brexit, unite the country - and then get on to all the other things that matter to people across the UK."
Sajid Javid offered similar sentiments, posting: "Congratulations @BorisJohnson on a resounding victory.
"Now let's come together as a party under his superb leadership, so we can deliver Brexit, unite our great country and defeat Corbyn."
However, those opposed to Mr Johnson's threat of a possible no-deal Brexit were more muted in their responses, with International Development Secretary Rory Stewart and Justice Secretary David Gauke both indicating their plans to return to the backbenches.
Meanwhile, Chancellor Philip Hammond, who has also said he will resign from his post, tweeted: "Congratulations @BorisJohnson! You have said very clearly that you are determined to do a deal with Brussels - and you will have my wholehearted support in doing so. Good luck!"
Some world leaders offered congratulations to Mr Johnson, including Australia's Scott Morrison and US President Donald Trump, who proclaimed "he will be great".
A man who could play a key role in Mr Johnson's campaign pledge, EU Brexit negotiator Michel Barnier, said he looked forward to "working constructively" with Boris Johnson to "achieve an orderly Brexit".
Mr Barnier added: "We are ready also to rework the agreed declaration on a new partnership in line with #EUCO guidelines."
Guy Verhofstadt, the European Parliament's chief Brexit co-ordinator, announced an extraordinary meeting would be held with Mr Barnier.
"The meeting will be followed by an official communication," he tweeted.
"Looking forward to defending the interest of all Europeans."
Back home, Labour leader Jeremy Corbyn warned Mr Johnson's interest in a no-deal Brexit and relationship with Mr Trump would harm the UK.
He also condemned the "unrepresentative" nature of Mr Johnson's election by the members of the Tory party.
"Johnson's no-deal Brexit would mean job cuts, higher prices in the shops and risk our NHS being sold off to US corporations in a sweetheart deal with Donald Trump," he tweeted.
"The people of our country should decide who becomes the Prime Minister in a General Election."
Mr Corbyn's sentiment was echoed by newly elected Liberal Democrat leader Jo Swinson.
"Britain deserves better than Boris Johnson," she tweeted.
Brexit Party leader Nigel Farage wished Mr Johnson well, praising his "do or die pledge to deliver Brexit" by October 31.
But he outlined the threat faced by Mr Johnson if he fails to achieve his target, asking: "Does he have the courage to deliver?"
Irish politicians were quick to welcome the new Prime Minister in waiting, making it clear they were happy to work with Mr Johnson.
However, Brexit remained the key priority in each message.
Taoiseach Leo Varadkar posted on social media: "Congratulations to Boris Johnson on his election as party leader.
"Look forward to an early engagement on Brexit, Northern Ireland and bilateral relations."
Later Tanaiste Simon Coveney first retweeted Mr Barnier, who had written about reworking "the agreed declaration on a new partnership in line with #EUCO guidelines", before writing his own post.
"Congratulations to Boris Johnson on becoming leader of the UK Conservative Party - we will work constructively with him and his Govt to maintain and strengthen British/Irish relations through the challenges of Brexit," Mr Coveney posted.