Once Humza Yousaf’s resignation is accepted by the King, parliament has 28 days to nominate a replacement.
The nomination process takes place in the Scottish Parliament this afternoon.
Leaders of other political parties can also put themselves forward during this process, although they would not expect to win. Any MSP can nominate a candidate, although it must be seconded by another member.
If there is more than one candidate, any who secures more than half of all votes will win the nomination.
If no-one reaches that threshold, the candidate with the fewest votes will be eliminated. This process will be repeated until the field is whittled down to two.
At that point, a candidate would only require a simple majority to win the nomination, meaning they only have to gain more votes than their opponent.
The SNP has 63 seats in the parliament, which means it does not have a majority.
However, the party’s nominee would be expected to win the vote and become first minister.