9 CASTELLS v. SPAIN JUDGMENT The applicant made a further reference to Article 20 of the Constitution in the summary of his complaints (suplico). 16. In his observations of 22 March 1984, the public prosecutor noted that Article 14 guaranteed equality before the law and not equality outside the law. As regards the complaint based on Article 23, it overlapped with the preceding complaint or was based on a misunderstanding: clearly a member of parliament did not carry out his duties only in the assembly, but outside it he did not enjoy any immunity; although he could, like any citizen, criticise the action of the Government, he should not forget that the freedom of expression had its limits, fixed by the Constitution. For his part, Mr Castells, by a letter of 21 May 1984, again offered to prove the truth of his statements, because that demonstrated "the violation by the contested judgment of the right to `receive and communicate true information by any means of dissemination', referred to in Article 20 of the Constitution". He also mentioned this right in his appeal (recurso de súplica) against the rejection of this offer by the Constitutional Court (20 July 1984) and in his observations of 21 February 1985. 17. The Constitutional Court dismissed the appeal on 10 April 1985. In summarising the applicant's complaints at point 2 of the "As to the Law" part of its judgment, it took together, like the public prosecutor, those relating to Articles 14 and 23, without referring to Article 20: alleged violation of the right to equality before the law, guaranteed under Article 14 taken alone or in conjunction with Article 23, inasmuch as the contested decision restricted the powers of monitoring, scrutiny and criticism of a senator. At point 6 it stated that parliamentary privileges were to be interpreted strictly as otherwise they could become instruments for infringing the rights of others; they lapsed when their holder had acted as a mere citizen, even in his capacity as a politician. At points 9 and 10 it considered the central issue: the right to rely on relevant evidence in presenting the defence case, and in particular to plead the defence of truth in respect of an offence of the type in question. The court noted in this connection: "In order to assess whether evidence which it is sought to adduce is relevant, it is necessary to establish a link between that evidence and the thema decidendi, which must first be determined on the basis of the parties' allegations. Except in the case of facts which are manifest or common knowledge, the court must not intervene in this regard, otherwise it will prejudge the merits, if only in part ... . It is preferable for the courts to avoid [such a preliminary assessment]; it does not however in itself infringe constitutional rights provided that the other defence rights are respected. Even though in the present case the court ought perhaps not to have anticipated its opinion on the defence of truth when assessing the relevance of the evidence, [that irregularity] therefore infringes the constitutional right to use relevant evidence - particularly where as here the decision is taken at a single level of jurisdiction - only if there has been a breach of a substantive right in issue.