Boris Johnson is due to become the 55th person to be prime minister of Great Britain and Northern Ireland.
In charge of a budget of around £800bn, the UK’s 150,000 troops and the power to press the nuclear button, it is a role that carries supreme responsibility.
Like starting any new job however, a few administrative tasks must be completed before they can get to work.
So what is Mr Johnson facing on the first day in office?
One unusual aspect about the transition from one prime minister to the next is the speed at which it takes place. The UK is usually without a premier for around one hour.
The outgoing PM, in this case Theresa May, visits the Queen at Buckingham Palace to tender their