251It must be borne in mind that, according to settled case-law, the system of competition established by Articles 81 EC and 82 EC is concerned with the economic consequences of agreements, or of any comparable form of concertation or coordination, rather than with their legal form. Consequently, in the case of agreements which have ceased to be in force, it is sufficient, in order for Article 81 EC to apply, that they produce their effects beyond the date on which they formally come to an end. It follows that the duration of an infringement must be appraised not by reference to the period during which an agreement is in force, but by reference to the period during which the undertakings concerned adopted conduct prohibited by Article 81 EC (see Joined Cases T-101/05 and T-111/05BASF and UCB v Commission [2007] ECR II-4949, paragraph 187 and the case-law cited).