Theresa May is the new Conservative Party leader and second female prime minister, taking charge of the UK at one of the most turbulent times in recent political history.
The 59-year-old home secretary's carefully cultivated image of political dependability and unflappability appears to have made her the right person at the right time as the fallout from the UK's vote to leave the EU smashed possible rivals out of contention.
Long known to have nurtured leadership hopes, Mrs May - whose friends recall her early ambition to be the UK's first female PM - could have reasonably expected to have had to wait until at least 2018 to have a shot at Downing Street.
But the EU referendum which David Cameron called and lost - the year after leading the party to its first election win in 23 years - turned political certainties on their head and, as other candidates fell by the wayside after the PM's own resignation, Mrs May emerged as the "unity" candidate to succeed him.
That her party should rally round her at such a time of national uncertainty is testament not only to the respect in which she is held across the party but to the fact that, in a world where political reputations can be shredded in an instant, Mrs May is the ultimate political survivor.
In the early days at Westminster she became known for her exuberant choice of footwear - her kitten heels became famous in political circles in the noughties, while she named a lifetime subscription to Vogue as the luxury item she would take to a desert island.
But it is her toughness which has become her political hallmark. She has coped with being one of only a small number of women in the upper echelons of the Conservative Party for 17 years and has been prepared to tell her party some hard truths - famously informing activists at the 2002 conference that "you know what some people call us - the nasty party".
Who is Theresa May?
- Date of birth: 1 October 1956 (aged 59)
- Job: MP for Maidenhead since 1997. Home Secretary since May 2010
- Education: Mainly state-educated at Wheatley Park Comprehensive School with a brief time at an independent school; St Hugh's College, Oxford
- Family: Married to Philip May
- Hobbies: Cooking - she says she owns 100 recipe books. Occasional mountain walks. On BBC Radio 4's Desert Island Discs in 2014, she chose Abba's Dancing Queen and Walk Like A Man, from the musical Jersey Boys, among her picks, alongside Mozart and Elgar.
- On her party's future: "(It is) nothing less than the patriotic duty of our party to unite and to govern in the best interests of the whole country. We need a bold, new positive vision for the future of our country - a country that works not for a privileged few but for every one of us." Says people want more than just a "Brexit PM" and has vowed to unify the Leave and Remain factions in the party.
Even before entering Downing Street, she made history by becoming the second longest serving home secretary in the past 100 years.
The daughter of a Church of England vicar, Hubert, who died from injuries sustained in a car crash when she was only 25, Theresa May's middle class background has more in keeping with the last female occupant of Downing Street, Margaret Thatcher, than her immediate predecessor.
Born in Sussex but raised largely in Oxfordshire, Mrs May - both of whose grandmothers are reported to have been in domestic service - attended a state primary, an independent convent school and then a grammar school in the village of Wheatley, which became the Wheatley Park Comprehensive School during her time there.
The young Theresa Brasier, as she was then, threw herself into village life, taking part in a pantomime that was produced by her father and working in the bakery on Saturdays to earn pocket money.
Friends recall a tall, fashion-conscious young woman who from an early age spoke of her ambition to be the first woman prime minister.
Like Margaret Thatcher, she went to Oxford University to study and, like so many others of her generation, found that her personal and political lives soon became closely intertwined.
In 1976, in her third year, she met her husband Philip, who was president of the Oxford Union, a well-known breeding ground for future political leaders.
The story has it that they were introduced at a Conservative Association disco by the subsequent Pakistani prime minister Benazir Bhutto. They married in 1980.
Her university friend Pat Frankland, speaking in 2011 on a BBC Radio 4 profile of the then home secretary, said: "I cannot remember a time when she did not have political ambitions.
"I well remember, at the time, that she did want to become the first woman prime minister and she was quite irritated when Margaret Thatcher got there first."
There are no tales of drunken student revelry, but Pat Frankland and other friends say May was not the austere figure she would later come to be seen as, saying she had a sense of fun and a full social life.
After graduating with a degree in Geography, May went to work in the City, initially starting work at the Bank of England and later rising to become head of the European Affairs Unit of the Association for Payment Clearing Services.
But it was already clear that she saw her future in politics. She was elected as a local councillor in Merton, south London, and served her ward for a decade, rising to become deputy leader. However, she was soon setting her sights even higher.
Mrs May, who has become a confidante as well as role model for aspiring female MPs - told prospective candidates before the 2015 election that "there is always a seat out there with your name on it".
In her case - like that of Margaret Thatcher - it took a bit of time for her to find hers. She first dipped her toe in the water in 1992, where she stood in the safe Labour seat of North West Durham, coming a distant second to Hilary Armstrong, who went on to become Labour's chief whip in the Blair government. Her fellow candidates in that contest also included a very youthful Tim Farron, who is now Lib Dem leader.
Two years later, she stood in Barking, east London, in a by-election where - with the Conservative government at the height of its unpopularity - she got fewer than 2,000 votes and saw her vote share dip more than 20%. But her luck was about to change.
The Conservatives' electoral fortunes may have hit a nadir in 1997, when Tony Blair came to power in a Labour landslide, but there was a silver lining for the party and for the aspiring politician when she won the seat of Maidenhead in Berkshire. It's a seat she has held ever since.
An early advocate of Conservative "modernisation" in the wilderness years that followed, Mrs May quickly joined the shadow cabinet in 1999 under William Hague as shadow education secretary and in 2002 she became the party's first female chairman under Iain Duncan Smith.
She then held a range of senior posts under Michael Howard but was conspicuously not part of the "Notting Hill set" which grabbed control of the party after its third successive defeat in 2005 and laid David Cameron and George Osborne's path to power.
This was perhaps reflected in the fact that she was initially given the rather underwhelming job of shadow leader of the House of Commons. But she gradually raised her standing and by 2009 had become shadow work and pensions secretary.
Nevertheless, her promotion to the job of home secretary when the Conservatives joined with the Lib Dems to form the first coalition government in 70 years was still something of a surprise - given that Chris Grayling had been shadowing the brief in opposition.
While the Home Office turned out to be the political graveyard of many a secretary of state in previous decades, Mrs May refused to let this happen - mastering her brief with what was said to be a microscopic attention to detail and no little willingness to enter into battles with fellow ministers when she thought it necessary.
While some in Downing Street worried that the Home Office was becoming her own personal fiefdom, she engendered loyalty among her ministers and was regarded as "unmovable" as her tough-talking style met with public approval even when the department's record did not always seem so strong.
In his memoir of his time in office, former Lib Dem minister David Laws says: "She would frequently clash with George Osborne over immigration. She rarely got on anything but badly with Michael Gove. She and Cameron seemed to view each other with mutual suspicion.
"I first met her in 2010. I was sitting in my Treasury office, overlooking St James's Park, me in one armchair and the home secretary in the other, with no officials present. She looked nervous.
"I felt she was surprised to find herself as home secretary. Frankly, I didn't expect her to last more than a couple of years."
Despite her liberal instincts in some policy areas, she frequently clashed with the then deputy prime minister and Lib Dem leader Nick Clegg, particularly over her plan to increase internet surveillance to combat terrorism, dubbed the "Snooper's Charter" by the Lib Dems.
After one "difficult" meeting with Mr Clegg, he reportedly told David Laws: "You know, I've grown to rather like Theresa May... 'She's a bit of an Ice Maiden and has no small talk whatsoever - none. I have quite difficult meetings with her. Cameron once said, 'She's exactly like that with me too!'
"She is instinctively secretive and very rigid, but you can be tough with her and she'll go away and think it all through again."
On the plus side crime levels fell, the UK avoided a mass terrorist attack and in 2013, she successfully deported radical cleric Abu Qatada - something she lists as one of her proudest achievements, along with preventing the extradition to America of computer hacker Gary McKinnon.
She was not afraid to take on vested interests, stunning the annual conference of the Police Federation in 2014 by telling them corruption problems were not just limited to "a few bad apples" and threatening to end the federation's automatic right to enrol officers as its members.
However, the Passport Office suffered a near meltdown while she has faced constant criticism over the government's failure to meet its promise to get net migration down to below 100,000 a year.
Labour MP Yvette Cooper, who went up against her in the Commons as shadow home secretary, told The Guardian: "I respect her style - it is steady and serious. She is authoritative in parliament - superficial attacks on her bounce off.
"The flip side is that she is not fleet of foot when crises build, she digs in her heels (remember the Passport Agency crisis in 2014 when the backlog caused hundreds to miss their holidays, and the Border Force crisis in 2011 when border checks were axed).
"And she hides when things go wrong. No interviews, no quotes, nothing to reassure people or to remind people she even exists. It's helped her survive as home secretary - but if you are prime minister, eventually the buck has to stop."
There was a bitter public row with cabinet colleague Michael Gove over the best way to combat Islamist extremism, which ended with Mr Gove having to apologise to the prime minister and Mrs May having to sack a long-serving special adviser - a turf war which is said to have led to a diminution in her admiration for the prime minister.
Where she stands on Brexit: Theresa May has insisted "Brexit means Brexit" and there will be no second referendum on the issue. She says official talks on leaving, which will begin when the UK triggers the so-called Article 50, won't begin until the end of 2016 at earliest. She has insisted the status of EU nationals in the UK won't change until a new "legal agreement" is reached but has yet to give a guarantee on their status. She says the best deal is needed to trade with the EU in goods and services but more control is needed to lower immigration.
Other policies: Theresa May has pledged a shake-up of boardroom ethics as part of which workers will be guaranteed representation on company boards while shareholders votes on executive pay deals will be made binding every year.
What the press say: "In a political party that struggles to shake off its elitist, old Etonian, yah-boo-sucks reputation, May represents a different kind of politician: a calm headmistress in a chamber full of over-excitable public schoolboys. She holds herself at one remove... her obdurate stance has earned her some vociferous critics. There are those who claim that, while she takes care never to sully her own hands with the grubby business of political backstabbing, she will send out her team to issue ferocious briefings against her rivals." The Guardian.
Former Conservative chancellor Ken Clarke also had run-ins with her and was recorded on camera ahead of an interview last week saying that Mrs May was good at her job but a "bloody difficult woman" - before adding as an aside, a bit like Mrs Thatcher. A reference to be Conservative leader can hardly come better than that.
Mrs May has never been one of the most clubbable of politicians and is someone who prefers not having to tour the tea rooms of the House of Commons - where tittle-tattle is freely exchanged.
She has rarely opened up about her private life although she revealed in 2013 that she had been diagnosed with Type 1 diabetes and would require insulin injections twice a day for the rest of her life - something she says she had come to terms with and which would not affect her career.
Generally thought to be in the mainstream of Conservative thinking on most economic and law and order issues, she has also challenged convention by attacking police stop and search powers and calling for a probe into the application of Sharia Law in British communities.
She also expressed a personal desire to withdraw from the European Convention on Human Rights but later said she would not pursue this as PM due to a lack of parliamentary support - an example of what many believe will be pragmatism in office.
Her social attitudes are slightly harder to pin down. She backed same sex marriage. She expressed a personal view in 2012 that the legal limit on abortion should be lowered from 24 to 20 weeks. Along with most Conservative MPs she voted against an outright ban on foxhunting.
What is undisputable is that at 59, Mrs May will be oldest leader to enter Downing Street since James Callaghan in 1976 and will be the first prime minister since Ted Heath who does not have children.
One of Westminster's shrewdest as well as toughest operators, Mrs May's decision to campaign for the UK to remain in the EU but to do so in an understated way and to frame her argument in relatively narrow security terms reaped dividends after the divisive campaign.
During what turned out to be a short-lived leadership campaign, Mrs May played strongly on her weight of experience, judgement and reliability in a time of crisis.
While her wider political appeal is, as yet, untested, Mrs May will not have to face a general election until May 2020 unless she decides to seek a fresh mandate - something she has seemingly ruled out.
While the early years of Mrs May's time in Downing Street may be dominated by the process of divorcing the UK from the EU and the deal she will be able to strike, she has also insisted she won't be content with the "safe pair of hands" tag that is often attached to her.
Brexit, she has said, won't be allowed purely to define her time in office and she has promised a radical programme of social reform, underpinned by values of One Nation Toryism, to promote social mobility and opportunity for the more disadvantaged in society.
But with a slender parliamentary majority of 17 and a nation still riven by divisions over the EU referendum and anxiety over the future, she will face as tough a task, some say even tougher, than any of her recent predecessors in Downing Street.