Cuestiones sobre principio de legalidad, ley penal en blanco y presunciones en el delito fiscal = Questions on the principle of legality, blanket criminal laws and presumptions in tax crimes

The present work examines the play of the principle of legality in criminal law in tax crimes. Starting from the conception of tax crime as a breach of duties crime, I will analyze how the presumptions employed in tax law affect the legal requirements of the crime in article 305 of the Spanish Criminal Code. This way, I will argue that legal tax rules integrate the requirements of article 305 CP, including its presumptions. However, I will put into doubt the constitutionality of presumptions when they bring into the criminal procedure conclusions that should be proved in accordance with the accusatory principle of procedure. In particular, I will put emphasis in three presumptions of tax law, that shall serve as examples: the presumption of retribution in article 6.5 LIRPF, the presumption on unjustified patrimonial gains on article 39 LIRPF and the procedure of indirect valuation of the tax debt in article 53 LGT. I will show a concept of tax law as a whole, in which most rules might be imposed and applied by administrative law means -with all its resources- and in which criminal law plays a part on punishing the breach of tax duties determined by a law (an Act of Parliament) and which generate a criminally relevant damage.