Must point (a) of the first subparagraph of Article 1(1) of Directive 98/59/EC of the Council of 20 July 1998 on the approximation of the laws of the Member States relating to collective redundancies (‘Directive 98/59/EC’) be interpreted as meaning that, for the purposes of determining the number of workers normally employed in an establishment, regard is to be had to the number of workers employed in the usual course of business at the time of the redundancy?

Must point (a) of the first subparagraph of Article 1(1) of Directive 98/59/EC be interpreted as meaning that, for the purposes of determining the number of workers normally employed in a user undertaking’s business, account may be taken of temporary agency workers employed there?

If the answer to the second question is in the affirmative: Which conditions apply to the taking into account of temporary agency workers for the purposes of determining the number of workers normally employed in a user undertaking’s business?