Branding him a liar, a coward or a joker, Europe's political class has greeted Eurosceptic Boris Johnson's appointment as Britain's foreign minister with a chorus of dismay.
French Foreign Minister Jean-Marc Ayrault eschewed the customary diplomatic niceties to ask how a man who had told lies as leader of the Leave campaign in last month's British EU referendum could be a credible interlocutor.
"I am not at all worried about Boris Johnson, but ... during the campaign he lied a lot to the British people and now it is he who has his back to the wall," Mr Ayrault told Europe 1 radio on Thursday.
"I need a partner with whom I can negotiate and who is clear, credible and reliable."
German Foreign Minister Frank-Walter Steinmeier said Johnson's appointment was a clear signal that Britain intended to leave the European Union and urged May to end uncertainty and give formal notice soon of London's intention to withdraw.
Speaking shortly before Mr Johnson was appointed, Mr Steinmeier said: "It is bitter for Britain. People there are experiencing a rude awakening after irresponsible politicians first lured the country into Brexit then, once the decision was made, bolted and instead of taking responsibility went off to play cricket.
"I find this outrageous but it's not just bitter for Britain. It's also bitter for the European Union."
That was a foretaste of the potentially hostile reception Mr Johnson can expect when he attends his first EU foreign ministers' meeting in Brussels on Monday.
Mr Johnson was accused of misleading voters by proclaiming that Britain was paying STG350 million ($NZ 646 million) a week to the EU that could be spent on the National Health Service.
The figure did not take account of London's budget rebate or of EU spending on public and private sector projects in the UK, and Leave campaigners have since acknowledged it was inflated.
The rambunctious former mayor of London has insulted or lampooned a series of world leaders including US President Barack Obama, Turkish President Tayyip Erdogan and both the Democratic and Republican candidates to succeed Mr Obama.
After the June 23 vote to leave the European Union, Mr Johnson took time off to play cricket and spurned a chance to stand as prime minister in place of fellow Conservative David Cameron, who had campaigned to stay in the EU.
Mr Johnson will not be in charge of talks about how the divorce will be arranged. Ms May named pro-Brexit former Conservative Party leader David Davis to a special ministerial role for that purpose.
France and other EU partners have urged Britain to trigger quickly the process of exiting the bloc so that a two-year period of talks about trade terms and other links can begin.
May: Give us time
Ms May faces the difficult task of negotiating Britain's exit from the EU after a June 23 public vote to leave.
"The prime minister explained that we would need some time to prepare for the negotiations," her spokesperson said on Thursday (local time), adding that Ms May had told Mr Juncker of her hope for a "constructive and positive" tone to the talks.
Ms May also backed the nomination of Julian King as Britain's new EU commissioner, made last week by her predecessor Mr Cameron, the spokesperson said.
The new British leader also spoke to US President Barack Obama on Thursday, underlining Britain's commitment to sustaining the countries' special relationship and key partnership on intelligence sharing.
"The prime minister underlined the ongoing commitment of the United Kingdom to be a key partner to the US on global issues including counter-terrorism and security," the spokesperson said.
Interest rates unchanged
The Bank of England has kept interest rates unchanged, wrong-footing many investors who had expected the first cut in more than seven years as Britain's economy reels from last month's Brexit vote.
The Bank said it was likely to deliver stimulus in three weeks' time, possibly as a "package of measures" once it has assessed how the June 23 referendum decision to leave the European Union has affected the economy.
"In the absence of a further worsening in the trade-off between supporting growth and returning inflation to target on a sustainable basis, most members of the Committee expect monetary policy to be loosened in August," the Bank said in minutes of its July meeting which ended on Wednesday.
"The precise size and nature of any stimulatory measures will be determined during the August forecast and Inflation Report round," it said.
Most economists taking part in a Reuters poll had expected the central bank to halve its Bank Rate to 0.25 percent in order to cushion the economy from the shock of the Brexit vote.
Sterling plunged more than 13 percent against the US dollar in the days after the vote and trillions of dollars were wiped off stock markets globally.
However, Ms May's quicker-than-expected appointment as Britain's new prime minister has helped settle nerves in financial markets.
BoE Governor Mark Carney was due to meet Britain's new finance minister Philip Hammond on Thursday. Hours after his appointment, Hammond said the government would do whatever was necessary to restore confidence in the economy and suggested a less aggressive approach to bringing down the budget deficit.
Carney sent a clear signal two weeks ago that stimulus was on the way over the summer in an attempt to show the economy was in safe hands as the country's political leadership crumbled after the EU vote.
But Carney has also suggested he does not favour a sharp cut in borrowing costs because of the possible effect on banks based in Britain, and he has said he did not want to follow the example of the European Central Bank and the Bank of Japan by cutting rates below zero.
In the minutes published on Thursday, the Bank said the composition of any additional stimulus measures "would take into account any interactions with the financial system."
It also said the extent of any further stimulus measures would be based on its updated forecasts.