What remedies are available in the last instance?

Ley Orgánica 2/1979, de 3 de octubre, del Tribunal Constitucional.

In effect since 25/10/1979 (last update in force since 05/11/2010)

https://www.boe.es/buscar/act.php?id=BOE-A-1979-23709

Articles53, 54 and 55.

Article 53

The Sala or, when appropiate, the Secci?n whenaddressing the substance of the matter, shall pronounce, in its judgement, anyof these decisions:

a)Granting/Conferment of Amparo (Otorgamiento de amparo.)

b) Denial/refusalof Amparo. (Denegaci?n de amparo.)

Article 54

When the Sala or, when appropriate, the Secci?nwill hear the Writ of Amparo in the case of Judges’ or Courts’ decisions, itshall be limited to concretize whether rights and freedoms of the complainanthave been violated and  to preserve andrestore those rights and freedoms, as well as it shall refrain from any otherconsideration about the jurisdictional bodies’ actions.

Article 55

1. The judgement granting Amparo will includeone or more of the following pronouncements:

a) Declarationof nullity of the decisi?n, act or judgement/ruling which had restrained thefull exercise of the protected rights or freedoms, with the determination, whenappropriate, of the extension of its effects.

b) Recognitionof the right or public freedom /civil liberty, according with itsconstitutionally stated content.

c) Restorationof the appellant in the integrity of his/her right or freedom/liberty via theadoption of the appropriate measures, when possible, for its conservation.