Boris Johnson has been elected as the new leader of the Conservative Party and is set to be appointed as Prime Minister tomorrow.
What will be the main defence issues the former Mayor of London faces when he moves into Downing Street?
National Security and Defence Spending
Firstly, defence spending will need addressing in order for the UK to be a significant player.
MPs and peers have warned the next PM walking into Number 10 is entering at a time when "the cornerstones of UK national security are being undermined".
The Joint Committee on the National Security Strategy's chairwoman, Dame Margaret Beckett, said "a reality check is urgently required" about the challenges facing the UK.
The committee also warned that the NATO target of spending 2% of GDP on defence may not be enough for the UK.
On Monday, just one day before the appointment of the new Tory leader, Jeremy Hunt announced the UK will be seeking to put together a European-led maritime protection mission in the Gulf.
Mr Hunt also announced HMS Duncan had been dispatched to join HMS Montrose, which is currently in the region and due to go in for "pre-planned maintenance" while continuing its deployment.
HMS Montrose was alerted when the British Steno Impero tanker was seized, however, she was too far away to stop its seizure.
Now, the next PM must look at how the UK will deescalate or assert more power in the region.
The size of the Royal Navy
"Our Royal Navy is too small to manage our interests across the globe if that's our future intentions and that's something the next Prime Minister will need to recognise," said defence minister Tobias Ellwood.
His comments come amid the increased tensions in the Gulf with Iran.
Again, this comes down to defence spending.
The realistic actions the Navy can take to grow their fleet all depends on how much money is allocated to the Armed Forces.
With the deadline of 31 October and only seven parliamentary working weeks away, this will most probably take most of the new PM's attention.
Operation Redfold, the military’s contingency planning operation, is preparing to respond to whichever Government department needs help in the event of a no-deal Brexit.
As many as 3,500 personnel are being held at readiness in case Britain leaves the European Union without a deal.