In a ruling issued on 30 May last, the Supreme Court resolved to ask the Constitutional Court for a preliminary ruling, as provided for in Additional Provision Five to the Public General Act [Ley Orgánica] governing the latter court, introduced via Public General Act 1/2010, known as the “ring-fencing” of provincial regulations.
The reason given by the Supreme Court for raising the issue of unconstitutionality is its doubt as to the validity of the provision set out in the last paragraph of subsection 1 of Article 102 of the NFGT of Bizkaia, which by excluding procedures begun by means of declarations or self-assessments from the six-month expiry period may be in breach of the harmonising regulation contained in point a) of Article 3 of the Basque Economic Agreement, which requires the Historical Territories to adapt to the terminology and concepts of the General Tax Act [Ley General Tributaria] in the drawing up of tax regulations.
In this case, in the scope of a procedure begun by means of a self-assessment, the tax authorities issued an injunction against a taxpayer and drew up a settlement after six months had elapsed from the date of the injunction, which means that if the expiry period envisaged in the General Tax Act for the data checking procedure is applicable then the period of limitation for the exercising of administrative power to determine the tax debt was exceeded and the settlement drawn up is null and void.
However the lower court ruling dated 23 September 2015 found nothing unlawful in the regulation of procedures contained in the NFGT and essentially confirmed the position of the tax authorities.
The ruling brought in by the Constitutional Court will be a matchless opportunity to dispel doubts as to the determination of the limits affecting the regulatory capabilities of the Historical Territories under the current wording of the Economic Agreement and the possibilities of diverging from the general state regulations on this matter.

Text of the Judgement