LONDON (AFP) - New British Prime Minister Boris Johnson was congratulated on Wednesday (July 24) by friend and foe alike, led by Russian President Vladimir Putin who said he hoped for an improvement in current icy ties with London.
Here are some reactions:
"The development of relations in the most varied areas would respond to the interests of our countries and our peoples," Putin said in a statement released by the Kremlin.
The Russian president wished Johnson "success" in office.
Already difficult relations were strained to breaking point last year by the attempted assassination of former Russian intelligence officer Sergei Skripal and his daughter in Salisbury, southern England.
London blames Moscow for the attack using the Soviet-era Novichok nerve agent but Russia has been completely dismissive of its claims.
German Chancellor Angela Merkel hailed the "deep friendship and close partnership" between the two countries, based on shared values and experience.
"I wish you lots of luck and success for the good of your country," said Merkel, the dominant European leader of recent years and a staunch defender of the European Union which Johnson wishes to leave post haste.
On Tuesday, US President Donald Trump - with whom Johnson is often compared, favourably and unfavourably - said, "He will be great!"
Trump, who has declared himself a big fan of Johnson, last week said the new premier would fix the "disaster" that former prime minister Theresa May had made out of trying to lead Britain out of the European Union.
"He's a different kind of a guy, but they say I'm a different kind of a guy too. We get along well. I think we'll have a very good relationship," Trump told reporters.
The reaction in the EU was mixed.
European Council president Donald Tusk was quick to congratulate Johnson, but added: "I look forward to meeting you to discuss - in detail - our cooperation."
Irish Prime Minister Leo Varadkar, whose country would be hardest hit by a "no deal" Brexit, was blunt.
"Any suggestion that there can be a whole new deal and negotiated in weeks or months is totally not in the real world," he said of Johnson's signature policy.
The incoming head of the European Commission, Ursula von der Leyen, offered her congratulations on Tuesday, noting: "There are many different and difficult issues to tackle together. We have challenging times ahead of us."
Von der Leyen takes office a day after Brexit is due to take place on Oct 31.
French President Emmanuel Macron said on Tuesday he wanted to get down to work with Johnson quickly.
"I want very much to work with him as quickly as possible and not just on European subjects and the continuation of negotiations linked to Brexit, but also on international issues on which we coordinate closely with Britain and Germany... like the situation in Iran."
Italy's Deputy Prime Minister Matteo Salvini added: "All the best Boris Johnson. The fact that the left describes him as more dangerous than (Salvini's far right party) The League makes him all the more likeable to me."
"I congratulate my former counterpart, @BorisJohnson on becoming UK PM," Iranian Foreign Minister Mohammad Javad Zarif tweeted on Tuesday amid a standoff over the seizure of oil tankers.
"Iran does not seek confrontation. But we have 1,500 miles of Persian Gulf coastline. These are our waters & we will protect them."
Indian Prime Minister Narendra Modi congratulated Johnson on his appointment.
"I wish you success and look forward to working with you to further strengthen India - UK partnership in all spheres," he said.