Member States shall take the necessary steps to ensure that all compulsory policies of insurance against civil liability arising out of the use of vehicles:
(a) cover, on the basis of a single premium and during the whole term of the contract, the entire territory of the Community, including for any period in which the vehicle remains in other Member States during the term of the contract; and
(b) guarantee, on the basis of that single premium, in each Member State, the cover required by its law or the cover required by the law of the Member State where the vehicle is normally based when that cover is higher.