1. By way of derogation from Article 16, and in exceptional circumstances only, a Member State may, in respect of a provider established in another Member State, take measures relating to the safety of services.

2. The measures provided for in paragraph 1 may be taken only if the mutual assistance procedure laid down in Article 35 is complied with and the following conditions are fulfilled:

(a) the national provisions in accordance with which the measure is taken have not been subject to Community harmonisation in the field of the safety of services;

(b) the measures provide for a higher level of protection of the recipient than would be the case in a measure taken by the Member State of establishment in accordance with its national provisions;

(c) the Member State of establishment has not taken any measures or has taken measures which are insufficient as compared with those referred to in Article 35(2);

(d) the measures are proportionate.

3. Paragraphs 1 and 2 shall be without prejudice to provisions, laid down in Community instruments, which guarantee the freedom to provide services or which allow derogations therefrom.