Article 20

1.          The prohibition on processing of personal data concerning a person’s membership of a trade union, referred to in Article 16, does not apply if the processing takes place by the relevant trade union or the trade union federation of which that union forms a part, to the extent that this is necessary in view of the objective of that trade union or federation.

2.          In the case, referred to in the first paragraph, no personal data shall be provided to third parties without the consent of the person concerned.