Article 11(5) of the Telecommunicatiewet, which concerns the transposition of Article 6 of Directive 97/66, is worded as follows: ‘1. In order to safeguard personal and private data, providers of a public telecommunications network and providers of a public telecommunications network shall ensure that, upon termination of a communication, traffic data processed concerning subscribers and users, as may be determined by general administrative measure, are to be subject to erasure or anonymity. 2 By way of exception to paragraph 1 above, traffic data may be processed only if and in so far as is necessary: (a) to calculate the bill of a subscriber or of the person who has undertaken in law to the provider to pay that bill, or for the purpose of payments for interconnection or other forms of access; (b) to enable the provider to undertake market research or to market its own telecommunications services, if the subscriber has given his consent thereto; (c) to examine disputes or determine them under Article 12(1) or to define the rules under Article 6(3), (d) to manage traffic, (e) to provide customers with traffic data provided such data relates to such customers, (f) to detect fraud; or (g) it is lawful by or under a law. 3 Measures implementing this article shall be adopted by general administrative measure. Such provisions may relate only to data which may be processed in conjunction with traffic data, to the purposes for which processing may take place, to the period within which processing is lawful, and to the persons who may be entrusted with processing.’ Pre-litigation procedure