In recent years and especially in the past two years, the Court of Justice of the European Union (ECJ) is becoming of great relevance in the interpretation and application of national labour law. Thus, at the root of various preliminary issues raised by national judiciary bodies of Spanish labour courts, the ECJ, in several recent judgments, is profoundly altering relevant fields, such as the calculation of numeric thresholds to determine when to carry out a collective dismissal, pursuant to Article 51 of the Workers Statute [Estatuto de los Trabajadores] (ET), as shown in our analysis below.

As a preliminary analysis of the resolutions adopted by the ECJ, it is important to analyse the nature of the issue of prejudiciality.

The procedure for the issue of prejudiciality takes place when a national court or tribunal submits a matter of European Union law to the ECJ for a resolution on the matter that allows the national court or tribunal to decide on the case that has been submitted and that it must resolve. The function of the issue of prejudiciality is to ensure a uniform and valid interpretation of EU law in all Member States.

This procedure is governed by Article 267 of the Treaty on the Functioning of the European Union (TFEU), which provides that: "When a matter is raised before any court of a Member State, that Court may, if it considers that a decision on the matter is necessary to enable it to issue a judgment, request the Court of Justice of the European Union to rule on that matter."

While lower courts have discretion to decide if they deem it relevant to submit a matter of prejudiciality or not, Article 267 of the TFEU excludes such discretion in the event that the ruling to be issued is a matter under the competence of the final appealable Court.

In practice, the use that national courts of Member States are making of this varies considerably, despite the provision contained in Article 267 TFEU, which seeks uniformity in the interpretation and application of European Union law.

The purpose of the TJEU is to establish the principles of EU law, but leaves the application of these principles to the national courts, with it being the case that discerning the limits under which the TFEU or national courts must act are not clear on many occasions. A principle originating in EU law may be defined in terms that leave little or no discretion to national courts, or it may happen that the principle is so vaguely defined that it allows absolute discretion to the national court when it is interpreted and applied.

A clear example of this is found without going deeper into the principle of equality and non-discrimination in Case C-595/12, of 6 March 2014, Loredana Napoli / Ministry of Justice – Department of Prison Administration, in which the ECJ does not discuss how to proceed under Italian law to ensure public security in a Member State, but resolves it by stating that in the event that these measures are likely to involve an exception to a fundamental right (the principle of equal treatment), they are obliged to respect the principle of proportionality. And it finishes concluding this Ruling by stating something that has led to an avalanche of prejudicial questions recently from Spanish courts and tribunals regarding the social order of their role within the EU framework and that "the national court is responsible for implementing, within its jurisdiction, the provisions of Union law; it is obliged to guarantee the full effect of those provisions, leaving, if necessary, any contrary provisions of national law unimplemented, of their own initiative, even if at a later time, without being obliged to await the prior repeal of these by legislative or other constitutional means".

And it is in this framework that the ECJ issued, in 2015, various rulings that relevantly alter the formula for calculation of the numerical thresholds laid out in Article 51 or the ET to determine when to carry out a collective dismissal. Thus, the first of these is the important ECJ Judgment of 13 May 2015 (Case C-392/13, Rabal Cañas), which, due to the issue raised by the judge of Labour Court no. 33 of Barcelona, for which the ECJ resolves considering that "Article 1.1, paragraph one, letter a) of Directive 98/59/EC must be interpreted as precluding national legislation which introduces, as the only reference unit, the company and not the workplace, (...) whereas, if the workplace were used as the reference unit, the dismissals involved should be classified as a 'collective dismissal' (...)". And it is through this Ruling that the ECJ has relevantly altered the calculation unit that to date has been used in Spain by Spanish courts, the Company, concluding that the calculation unit should be the workplace, without prejudice to being able to use the company as a calculation unit provided that it favours the implementation of a collective dismissal.

Subsequently, the ECJ Judgment of 11 November 2015 (Case C-422/14, Cristian Pujante Rivera and Gestora Clubs Dir, S.L.), once again resolving a preliminary ruling submitted by the same judicial body, Labour Court no. 33 of Barcelona, brings up the significance that should be given to the expression "workers who are usually employed" in the workplace concerned and to the concepts of "dismissal" and "termination of the employment contract, which is similar to dismissal" contained in Article 51 of the ET and the method of calculation of the number of workers dismissed.

Regarding the first question, it is understood that the workers with a contract for a term or for a specific task must be considered to be included among the workers who are "usually" employed for the purposes of calculating the workforce of the company affected by a collective dismissal.

In regard to the second question, it states that in order to prove the existence of a collective dismissal, it is required that the dismissals to be calculated total at least five, with the concept of "dismissal" required to be interpreted not as the termination of an employment contract similar to a dismissal, but exclusively as dismissals in the strict sense of the word.

Finally, regarding the third question, which examines whether the termination of the contract at the request of a worker due to a change in the employment contract made pursuant to Article 41 of the ET must be understood as "termination of the employment similar to the dismissal" determines that "Directive 98/59 must be interpreted as meaning that the fact that a business owner proceeds, unilaterally and to the detriment of the worker, to make a substantial modification of essential elements of the employment contract for reason that are not inherent in the individual worker is understood in the concept of dismissal used in Article 1, section 1, paragraph, letter a), of said Directive".

As can be seen, the solutions provided by the ECJ for the above issues are very relevant, as they profoundly affect our domestic law, generating a flurry interpretive questions about the handling of a collective dismissal, which demonstrate the urgent need for action by our legislative power, which, driven by its own community jurisprudence, should ultimately proceed to clarify the wording of Article 51 of the ET and related legislation.

There is thus no denying the significant role played by the ECJ as an interpreter of Community law, valuing its interest in opening Community legislation up to new spaces, as yet unexplored. It is true that the on-going ECJ rulings on labour, especially in the last two years, show some insufficiency in Community labour legislation that should be complemented with case law and legislative interventions. But what we must clearly conclude is that any legal practitioner in the field of labour law must know and act, keeping in mind in any case European law and the doctrine of the ECJ, which will increasingly influence our Spanish courts, with everything that implies for labour stakeholders. Thus, to properly advise our clients, we have to not only know and analyse domestic legislation and jurisprudence, but we must also increasingly take into account Community legislation and the interpretation provided by the ECJ.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.