Swedish governmental line of succession

The Swedish constitution of 1974 allows the prime minister of Sweden to appoint one of the ministers in the cabinet as deputy prime minister (ställföreträdande statsminister, also unofficially known as vice statsminister, "Vice Prime Minister"), in case the prime minister for some reason is prevented from performing his or her duties. However, if a deputy prime minister has not been appointed, the minister in the cabinet who has served the longest time (and if there are several with equal experience the one who is oldest) takes over as head of government.

Source: Wikipedia — Swedish governmental line of succession (CC BY-SA 4.0)