After weeks of campaigning, Liz Truss has won the battle to become the new leader of the Conservative Party and the UK's next Prime Minister.
The Foreign Secretary secured 57% of votes from Tory party members in the head-to-head contest with former Chancellor Rishi Sunak.
The result was announced on the same day that Parliament returned from its summer recess, a break which has seen many challenges pile up in the next Prime Minister's in-tray.
Read more: Arlene Foster's pro-Union project suffers setback as Ruth Davidson dismisses tour claims
From the cost-of-living crisis to Russia's continuing invasion of Ukraine, Boris Johnson's successor will have plenty of issues to grapple with over the coming months.
And many of the challenges focus on Northern Ireland. Here is a rundown of some key issues affecting the region which the new occupant of Number 10 will have to consider:
1. Choosing a Secretary of State
The new Prime Minister will choose their own Cabinet team including potentially replacing Shailesh Vara as Northern Ireland secretary.
Mr Vara, who backed Mr Sunak in the Tory leadership race, was only appointed in July after Brandon Lewis resigned during the turmoil that ended Mr Johnson's premiership.
Conor Burns, currently a junior minister in the Northern Ireland Office, has been tipped as a possible contender, but the Belfast-born MP could be considered too linked to the Johnson era.
During the recent Tory leadership hustings in Northern Ireland, a local Tory member asked Liz Truss: "Are you just going to give us another fly-in, fly-out, absentee political landlord?"
Ms Truss said the person she would appoint would be the "absolute best at delivering for the people of Northern Ireland".
2. Brexit's Northern Ireland Protocol
Both Tory leadership contenders have pledged to "fix" the Protocol, which was designed to prevent a hard border with the Irish Republic but has led to trade barriers with Great Britain.
Focus remains on the passage through Parliament of divisive legislation aimed at overriding parts of the post-Brexit Irish Sea trade agreement with the European Union.
Neither Ms Truss, who introduced the Northern Ireland Protocol Bill, nor Mr Sunak have resiled from the plan, but it could face problems in the House of Lords if peers are unhappy with its contents.
There have also been reports that Ms Truss could trigger Article 16, a Protocol clause allowing either side to take safeguarding measures if trading arrangements lead to serious economic, societal or environmental difficulties.
With both candidates leaving the door open to fresh EU negotiations, there is still the potential the impasse could be resolved without the legislation or Article 16 being used.
3. Cost-of-living crisis
How best to tackle soaring energy bills facing households and businesses over the coming months is shaping up to be the defining issue of the incoming Prime Minister's tenure.
With Labour extending its polling lead over the Conservatives, Boris Johnson's successor faces an uphill battle to ease the financial pressures ahead of the next general election.
In Northern Ireland focus has remained on delivering a £400 energy bill discount, with Sinn Féin and DUP clashing over whether Stormont's collapse will delay the UK government subsidy.
The Prime Minister will want to see this delivered, but the new occupant of No 10 also faces the headache of ensuring that any further funding announcements will extend to Northern Ireland.
Normally what would happen is an uplift in spending in England means an equivalent amount of money would be given to the Stormont Executive to determine how to distribute.
But without an Executive, the current hundreds of millions of unallocated Stormont funding which otherwise cannot be spent may simply continue to rise.
4. Another Stormont election?
Restoring devolved government at Stormont will be a key challenge for the incoming Prime Minister - but the clock is ticking on fresh Assembly elections.
Under legislation introduced earlier this year, Stormont's current caretaker ministers can only remain in post for up to 24 weeks without a new Executive being formed.
It means if there is still no new devolved government formed by October 28, the Secretary of State will be required to call a snap election within the subsequent 12 weeks.
With the DUP continuing to block power-sharing in protest over the Northern Ireland Protocol, there could be a snap Assembly election by mid-January 2023 at the latest.
The new Prime Minister and their Secretary of State will have to decide whether to follow through with a snap election, or whether to move the goalposts.
5. Troubles legacy bill
The Northern Ireland Troubles (Legacy and Reconciliation) Bill has already been through the House of Commons and heads to the House of Lords in the autumn.
It proposes a form of amnesty for perpetrators of Troubles-related crimes in exchange for co-operation with a new judge-led information retrieval body, and also ends inquests and civil proceedings related to the conflict.
The Bill has been opposed by political parties and victims groups in Northern Ireland, as well as by the Irish government.
But the UK government argues the plan will provide better outcomes for victims, survivors and veterans.
The Conservatives have a majority at Westminster to press ahead, but the Prime Minister will ultimately have to decide whether to do so despite vocal opposition in Northern Ireland.
6. Abortion and Irish language plans
The new Prime Minister will likely continue with efforts under Mr Johnson's administration to directly commission abortion services in Northern Ireland and legislate for the Irish language.
MPs in June formally approved moves to allow the UK government to directly commission abortion services in the region amid a political impasse at Stormont on the issue.
The Identity and Language (Northern Ireland) Bill has also been making its way through the House of Lords.
The draft laws include two commissioner roles – one for the Irish language and another for the Ulster Scots/Ulster British tradition.
The government intervened following a stand-off between the DUP and Sinn Féin over implementing Irish language laws envisaged in the 2020 'New Decade, New Approach' deal.
7. Tackling Tory turmoil?
The appointment of a new Conservative Party leader comes at a time when the party in Northern Ireland has been hit with internal disputes and dismal election results.
Former chair of the NI Conservatives Alan Dunlop recently said his bid to rejoin the party had been rejected.
The businessman quit the party last year over Boris Johnson's handling of the Northern Ireland Protocol and disagreements over the approach taken by some local members.
In May's Assembly election the party fielded only one candidate, chairman Matthew Robinson, who received just 254 first-preference votes.
Some local Conservatives have been calling for more support from the party centrally in a bid to boost their electoral performance.
READ NEXT:
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- Liz Truss and Rishi Sunak set out stalls on Northern Ireland ahead of Tory leadership hustings
- Conservative members in Northern Ireland on what they think of final two leadership contenders
- BBC's Stephen Nolan was lined up to host Tory leadership hustings in Northern Ireland
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