The emotional resignation of Britain’s prime minister Theresa May on Friday immediately sparked a fierce leadership battle.
Within half an hour of her announcement, candidates had already begun rallying their contemporaries for support in the race for power.
It came as the country’s opposition leader Jeremy Corbyn called for an immediate election.
Across Europe leaders paid tribute to her tenure describing her as “determined and courageous”.
Jean-Claude Juncker, the European Commission president, said he had “no personal joy” in hearing the announcement and described her as “a very courageous woman”.
The EU's chief Brexit negotiator Michel Barnier said: "I would like to express my full respect for @theresa_may and for her determination, as Prime Minister, in working towards the #UK's orderly withdrawal from the EU."
The Republic of Ireland’s premier Leo Varadkar said: “Politicians throughout the EU have admired her tenacity, her courage and her determination during what has been a difficult and challenging time.
“Theresa May strove to chart a new future for the United Kingdom. I want to wish her the very best for the future. I look forward to working closely with her successor.”
Mrs May’s term in office has been dominated by bitter infighting, which has seen 36 ministerial resignations, and her failure to deliver Brexit.
An aide for French President Emmanuel Macron said “rapid clarification” was now needed from the UK on Brexit.
“Our relations with the United Kingdom are critical in all areas. It is too early to speculate on the consequences of [May’s] decision,” he added.
The UK is still set to leave the EU without a deal at the end of October.
The prime minister of the Netherlands Mark Rutte spoke with Mrs May following her announcement, he later tweeted: “The deal reached between the European Union and Britain for an orderly Brexit remains on the table.”
The prime minister will meet EU leaders one last time at a summit in Brussels on Tuesday.
Mrs May made the announcement on the steps of Downing Street in London after three years at the helm.
She will formally resign on June 7 after taking part in D-Day commemorations in France and hosting US President Donald Trump on a state visit to the UK.
On Friday, his daughter Ivanka Trump tweeted: "Prime Minister @theresa_may fought hard in a challenging time and showed great courage and dignity in service of her country."
As the news broke, the value of GBP Sterling rose briefly climbing higher against the Euro and US dollar but just an hour later the markets had returned to normal.
A new party leader is expected to be appointed by the end of July.
In her leaving speech, Mrs May said: “I will shortly leave the job that it has been the honour of my life to hold — the second female prime minister but certainly not the last,” she said,
“I do so with no ill-will but with enormous and enduring gratitude to have had the opportunity to serve the country I love.
“But it is now clear to me that it is in the best interests of the country for a new prime minister to lead that effort.”
Those seeking to replace her must now gained the support of their party’s fellow politicians.
Just four hours after her speech, Foreign Secretary Jeremy Hunt became the first cabinet minister to confirm his bid to become the next leader.
It came an hour after he tweeted: “I want to pay tribute to the PM today. Delivering Brexit was always going to be a huge task, but one she met every day with courage & resolve.
“NHS will have an extra £20bn thanks to her support, and she leaves the country safer and more secure. A true public servant.”
The other leading contenders include former Foreign Secretary Boris Johnson, who campaigned for Brexit in the 2016 Referendum, Environment Secretary Michael Gove and Dominic Raab.
Mr Johnson tweeted: "A very dignified statement from @theresa_may. Thank you for your stoical service to our country and the Conservative Party. It is now time to follow her urgings: to come together and deliver Brexit."
However, Mr Corbyn welcomed the move and urged her replacement to call an election.
“Theresa May is right to resign,” he tweeted.
“She's now accepted what the country's known for months: she can't govern, and nor can her divided and disintegrating party.
“Whoever becomes the new Tory leader must let the people decide our country’s future, through an immediate General Election.”
Liberal Democrat leader Sir Vince Cable has called for a second referendum on Brexit.
“The prime minister is right to recognise that her administration has reached the end of the road. Sadly her compromises through the last three years have too often been with the right-wing of her own party, rather than about bringing the country together,” he said.
“Conservative Party interest has always trumped national interest, and yet Conservative MPs continue to demand an ever more extreme Brexit policy. The best and only option remains to take Brexit back to the people. I believe the public would now choose to stop Brexit.”
Mrs May will now remain as prime minister after June 7 in a caretaker role until a replacement is found.