1. Actions for annulment - Natural or legal persons - Interest in bringing proceedings - Claim by tenderer whose bid was not accepted - Admissibility (Art. 230, fourth para., EC) 2. European Community public procurement - Conclusion of a contract following an invitation to tender - Discretion of the institutions - Judicial review - Limits 3. Procedure - Introduction of new pleas in law in the course of the proceedings - Conditions - New plea - Concept (Rules of Procedure of the Court of First Instance, Arts 44(1)(c)and 48(2))