Article 4
1. Spain shall take all necessary measures to recover from the recipients the aid referred to in Article 2 made available to them unlawfully. 2. Recovery shall be effected without delay and in accordance with the procedures of national law, provided that these allow immediate and effective execution of this Decision. The aid to be recovered shall include interest from the date on which it was at the disposal of the beneficiaries until the date of its recovery. Interest shall be calculated at the reference rate used for calculating the grant-equivalent of regional aid.