Theresa May will become the second woman after Margaret Thatcher to hold Britain's highest office when David Cameron formally hands over power to her on Wednesday. Cameron announced that he would step down hours after the country voted to leave the European Union, triggering a leadership contest in his Conservative Party.
May emerged as the winner of that contest on Monday, following the shock resignation of former London mayor Boris Johnson, who had been the face of the campaign to leave the EU. She will parachute into Number 10 Downing Street at one of the most turbulent periods in modern British history.
As the new Prime Minister, May will lead negotiations with the EU to form a new relationship between London and Brussels. After she invokes article 50 of the Lisbon treaty, which begins the formal process to leave the bloc, she will need to balance markets and migration.
Many of Britain's businesses want free access to the single market. But with immigration as the key issue in last month's referendum, the majority of Britons do not want EU citizens to move freely into the country. The tension between those two positions will form the basis of much of the talks.
A steep rise in immigration from Africa and the Middle East, mainly from Eritrea and Syria, was a key development during May's tenure as the UK's home secretary. At a Conservative party conference in October, May gave a speech asserting that immigration is undercutting wages for British workers and new arrivals are not benefiting the economy in any way.
"It certainly suggests that Mrs May is determined to oppose the idea that adaptation to an age of mass migration is a more realistic answer than resisting it," the Guardian newspaper said in an editorial.
She came under fire for missing a target to reign in the flow of non-European migrants to below 100,000 a year. Last year, 330,000 people arrived in Britain.
Her response to greater immigration from Africa was to agree a £200m aid package for Sudan, Ethiopia, Somalia, Kenya and Uganda as well as countries hit by the El Nino drought. “We want to work with African countries, the countries of origin, to ensure people don’t feel the need to make this journey to Europe," May said.
May has also championed greater policing in Libya, from where many African migrants take boats to Europe. "British immigration officials worked [in Libya] with their European and Libyan counterparts to stop illegal immigration from Africa at its source."
But she has been criticised for cracking down on immigration by making it more difficult for people to gain asylum in Britain, even if they are fleeing war.
Trade is another important issue between Britain and Africa. May will need to work with James Duddridge, the UK's minister for Africa, to form dozens of new trade agreements between Britain and African countries as well as their regional blocs. These agreements had previously been struck through the EU.
Duddridge told Radio France International: "The complexities of Africa and crossover of issues probably mean that the UK is going to play a more active role in African security and play a greater role in Africa militarily regardless of whether we remain within the EU or whether we exit.”
May has a complicated relationship with gay rights. After voting to keep a law that bans schools from purposefully promoting homosexuality, May voted to legalise same-sex marriage. But during her time as home secretary, the UK has started to require asylum seekers to prove their sexual orientation to eliminate fraudulent applicants.
A new election?
After Cameron announced his resignation there were widespread calls for a fresh general election. These calls have been ignored by May, who said "there should be no general election until 2020" when she launched her campaign to become leader of the Conservative Party.
May's lack of foreign policy experience make it hard to predict what her overseas priorities will be after she assumes office. But it is safe to assume that negotiating the UK's new relationship with the EU will take up most of her time.