Grounds for refusing the questioning of one's own party
Spanish Procedural Law (the so called LEC) does not allow the call for the questioning of the party itself. The parties have other procedural channels to present their version of the facts (lawsuit, answer to the suit, conclusions report, etc.), without the fact that the party could subsequently reiterate it (or even qualify it) by means of a statement in the act of the trial, no matter how eloquent the party may be, prove what your version of events continues to be (see Judgment of the Barcelona Provincial Court of June 30th, 2009, Rec. 826/2008).
The answer to the question raised in this regard, which is normally obtained from the Courts, is negative as it is considered that art. 301.1 LEC prohibits the questioning itself. In this sense, for example, the Judgment of the Provincial Court of Murcia (Section 1) of February 17th, 2004 states in this regard in its second law foundation (JUR 2004/169932):
"Lastly, no defenselessness has caused the appellant to waive the interrogation, since defenselessness can never be caused by the deprivation of a right that they have never had. In accordance with Article 301 of the the Civil Procedure Law (RCL 2000, 34, 962 and RCL 2001, 1892), no one can interest their own questioning. The right of the party to be questioned by his lawyer arises after the opportunity to question the other, who has interested such means of proof (article 306.1), not before. Consequently, if the proposer waives the interrogation, no right has arisen for the litigant initially called to answer the questions and, therefore, the party is not made defenseless. In addition, the answers that the party had given would only have evidentiary efficacy insofar as they were harmful to it (article 316.1), so that eagerness to submit him to this means of proof is not understood."
This resolution also raises the question of the usefulness of the interrogation of the own party, particularly considering that the party's manifestations would only have evidentiary efficacy if they were harmful to the very party (art. 316.1 LEC). Therefore, it really calls into question the very usefulness of that interrogation.