The provisions of Articles 4, 6, 7 and 8 shall apply to vehicles normally based on the territory of one of the Member States:

1. (a)

   after an agreement has been concluded between the national insurers’ bureaux under the terms of which each national bureau guarantees the settlement, in accordance with the provisions of national law on compulsory insurance, of claims in respect of accidents occurring in its territory, caused by vehicles normally based in the territory of another Member State, whether or not such vehicles are insured;

2. (b)

   from the date fixed by the Commission, upon its having ascertained in close cooperation with the Member States that such an agreement has been concluded;

3. (c)

   for the duration of that agreement.