this Directive by 2 December 2003 at the latest or may entrust the social partners, at their joint request, with the implementation of this Directive as regards provisions concerning collective agreements. In such cases, Member States shall ensure that, no later than 2 December 2003, the social partners introduce the necessary measures by agreement, the Member States concerned being required to take any necessary measures to enable them at any time to be in a position to guarantee the results imposed by this Directive. They shall forthwith inform the Commission thereof. In order to take account of particular conditions, Member States may, if necessary, have an additional period of 3 years from 2 December 2003, that is to say a total of 6 years, to implement the provisions of this Directive on age and disability discrimination. In that event they shall inform the Commission forthwith. Any Member State which chooses to use this additional period shall report annually to the Commission on the steps it is taking to tackle age and disability discrimination and on the progress it is making towards implementation. The Commission shall report annually to the Council. When Member States adopt these measures, they shall contain a reference to this Directive or be accompanied by such reference on the occasion of their official publication. The methods of making such reference shall be laid down by Member States. Article 19 Report 1. Member States shall communicate to the Commission, by 2 December 2005 at the latest and every five years thereafter, all the information necessary for the Commission to draw up a report to the European Parliament and the Council on the application of this Directive. 2. The Commission's report shall take into account, as appropriate, the viewpoints of the social partners and relevant non-governmental organisations. In accordance with the principle of gender mainstreaming, this report shall, inter alia, provide an assessment of the impact of the measures taken on women and men. In the light of the information received, this report shall include, if necessary, proposals to revise and update this Directive. Article 20 Entry into force This Directive shall enter into force on the day of its publication in the Official Journal of the European Communities. Article 21 Addressees This Directive is addressed to the Member States. Done at Brussels, 27 November 2000. For the Council The President É. Guigou (1) OJ C 177 E, 27.6.2000, p. 42. (2) Opinion delivered on 12 October 2000 (not yet published in the Official Journal). (3) OJ C 204, 18.7.2000, p. 82. (4) OJ C 226, 8.8.2000, p. 1. (5) OJ L 39, 14.2.1976, p. 40. (6) OJ L 180, 19.7.2000, p. 22. (7) OJ L 225, 12.8.1986, p. 43. (8) OJ C 186, 2.7.1999, p. 3.