The Bank of England kept interest rates unchanged, wrong-footing many investors who had expected the first cut in more than seven years. But it said it was likely to deliver a stimulus in three weeks' time, once it has assessed the fallout from the June 23 vote for Brexit. The pound rose sharply on the news, while shares fell.
A day after replacing David Cameron, May moved to impose her authority with one of the most sweeping government reshuffles for decades. She axed a handful of prominent ministers including Justice Secretary Michael Gove, a leading Brexit campaigner who had staged his own bid for prime minister.
One of her most contentious appointments is Boris Johnson as foreign secretary, who compared the aims of the EU to those of Hitler and Napoleon during the referendum campaign. The surprise choice drew a withering response from French Foreign Minister Jean-Marc Ayrault, who described the former London mayor as a liar.
Three weeks after the shock vote for 'Brexit', May's government faces the complex task of extricating Britain from the 28-nation EU while trying to protect the economy from feared disruption to confidence, trade and investment.
New chancellor of exchequer Philip Hammond signalled he would take a less aggressive approach to cutting the budget deficit than his predecessor George Osborne, who was dumped on Wednesday.
"Markets do need signals of reassurance, they need to know that we will do whatever is necessary to keep the economy on track," Hammond said.
"Of course we've got to reduce the deficit further but looking at how and when and at what pace we do that ... is something that we now need to consider in the light of the new circumstances that the economy is facing," he said.
May, who had favoured a vote to stay in the EU, must now decide when and how to start official divorce proceedings from the other 27 countries, who are pressing her to move quickly to lift the uncertainty now hanging over them all.
In her first words to the nation on Wednesday, she promised to champion social justice and to help ordinary Britons in their struggle to make ends meet.
"The government I lead will be driven not be the interests of the privileged few, but by yours. We will do everything we can to give you more control over your lives," she said.
Britons chose Brexit despite a barrage of warnings that severing ties would create huge uncertainty and plunge the economy into recession. The winning 'Leave' campaign dismissed what it called 'Project Fear', saying Britain would prosper if it regained independence from Brussels.
In one of her first acts, May dismissed chancellor Osborne, a figure synonymous with austerity policies and a leading voice among those who had warned that leaving the EU would spell economic doom.
On Thursday she followed up by removing the justice, education, culture and cabinet office ministers, while the NorthernIrelandminister also quit.
Veteran right-wingers David Davis and Liam Fox have been named, respectively, as Secretary of State for Exiting the European Union and head of a new international trade department, both key positions in the arduous negotiations ahead.
Asked if Britain would launch the formal process of quitting the EU by the end of this year, chancellor Hammond told LBC radio: "No, that's a decision that we haven't made yet."
He added: "We've now got the key players who will be involved in this decision-making process in place, and when the prime minister has finished making her appointments later today I am sure that we will sit down and start to talk about Britain's negotiating strategy and how we are going to take it forward."
Hammond said the decision to vote for Brexit would mean Britain would leave the EU's tariff-free single market, and it would then have to negotiate a new deal as a trading partner rather than a member.
"The question is how we negotiate with the European Union not from the point of view of being members but from the point of view of being close neighbours and trade partners," he added.
'BACK AGAINST THE WALL'
The biggest surprise so far has been the appointment of Johnson, until recently seen as May's top rival for prime minister, as foreign secretary.
Johnson was the figurehead of the successful Leave campaign, but since the referendum had suffered widespread criticism and ridicule for failing to present a clear Brexit plan and swiftly dropping out of the leadership race.
With his unkempt blonde hair, bumbling humour and penchant for Latin quotations, the man known to Britons simply as "Boris" will be the government's most colourful figure, but a contentious choice for conducting sensitive diplomacy with world leaders.
Reaction from Paris to his appointment was blunt.
"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 against the wall," foreign minister Ayrault said.
He said in the current climate he needed a "clear, credible and reliable" partner. "We cannot let this ambiguous, blurred situation drag on ... in the interests of the British themselves."