[4] From 1977 to 1981, Suárez appointed his Finance Ministers as Second Deputies and during his short term, Calvo-Sotelo did the same.

Socialist PM González never appointed a second deputy prime minister during his almost 14 years of premiership.

The conservative PM Mariano Rajoy did not appoint a second deputy prime minister.

[5] In July 2021, Labour and Social Economy Minister Yolanda Díaz was appointed as second deputy PM.

The position is regulated in the Government Act of 1997 and it only specifies that the raison d'être of the office is to replace the Prime Minister when the office is vacant, or the premier is absent or ill.[6] The second deputy prime minister only assumes this responsibility if the first deputy is unable to fill the role.