1. The existence and validity of a contract, or of any term of a contract, shall be determined by the law which would govern it under this Regulation if the contract or term were valid.

2. Nevertheless, a party, in order to establish that he did not consent, may rely upon the law of the country in which he has his habitual residence if it appears from the circumstances that it would not be reasonable to determine the effect of his conduct in accordance with the law specified in paragraph 1.