20. The Court has emphasized that one of the main purposes of the separation of public powers is the guarantee of the independence of judges, which is intended to avoid the judicial system in general, and its members in particular, possibly being subject to undue constraints in the exercise of their function from organs outside the Judiciary or even from those judges who occupy functions of review or appeal. The Inter-American Court has understood that the independence of the Judiciary is “essential for the exercise of the judicial function.” In accordance with its consistent case law, the Inter-American Court has considered that the following guarantees arise from judicial independence: an adequate appointment procedure; tenure in office, and a guarantee against external pressure. The Court has referred to the right to an independent judge established in Article 8(1) of the Convention both with regard to the accused (right to be tried by an independent judge), and has also referred to the guarantees that the judge – as a public official – must have, in order to make judicial independence possible.21 21. In European case law, there is a close relationship between the guarantees of an “independent” court and an “impartial” court and, in some cases the two concepts have been dealt with as almost interchangeable.22 Thus, without becoming analogous, for some experts the concepts of the independence and the impartiality of a court are evidently complementary, so that the European Court of Human Rights (hereinafter “the ECHR) has accepted this close relationship to the point of examining them together.23 22. The ECHR has recognized that judicial impartiality has two dimensions: one of a personal character related to the circumstances of the judge, to the formation of his own personal convictions in a specific case, and the other, of a functional nature, exemplified by the guarantees that should be offered by the court responsible for delivering judgment, and that are established based on organic and functional considerations.24 The former must be presumed while the contrary has not been 21 Cf. Case of the Constitutional Tribunal (Camba Campos et al.) v. Ecuador. Preliminary objections, merits, reparations and costs. Judgment of August 28, 2013. Series C No. 268, paras. 188 to 196. See also: Case of the Constitutional Court v. Peru. Merits, reparations and costs. Judgment of January 31, 2001. Series C No. 71, paras. 66 to 85; Case of Palamara Iribarne v. Chile. Merits, reparations and costs. Judgment of November 22, 2005. Series C No. 135, paras. 145 to 161; Case of Apitz Barbera et al. (“First Contentious Administrative Court”) v. Venezuela. Preliminary objection, merits, reparations and costs. Judgment of August 5, 2008. Series C No. 182, para. 55; Case of Reverón Trujillo v. Venezuela. Preliminary objection, merits, reparations and costs. Judgment of June 30, 2009. Series C No. 197, paras. 67 to 81; Case of Chocrón Chocrón v. Venezuela. Preliminary objection, merits, reparations and costs. Judgment of July 1, 2011, paras. 95 to 111, and Case of Atala Riffo and daughters v. Chile. Merits, reparations and costs. Judgment of February 24, 2012. Series C No. 239, para. 186. 22 García Roca, Javier and Vidal Zapatero, José Miguel, “El derecho a un tribunal independiente e imparcial (art. 6.1): Una garantía concreta de mínimos antes que una regla de justicia” in García Roca, Javier and Santolaya, Pablo, La Europa de los Derechos. El Convenio Europeo de Derechos Humanos, 2ª ed., Madrid, Centro de Estudios Políticos and Constitucionales, 2009, p. 377. 23 Casadevall, Josep. El Convenio Europeo de Derechos Humanos, el Tribunal de Estrasburgo y su Jurisprudencia, Valencia, Tirant lo Blanch, 2012, p. 279. 24 In the text, we use the following terms when referring to the two aspects of impartiality analyzed by the ECHR: functional impartiality and personal impartiality. Also, in order to analyze these aspects of impartiality, we use two tests: the objective test and the subjective test. We are making this clarification because, at times, legal doctrine indicates that the applicable expressions would be “subjective impartiality” and “objective impartiality” to refer to the sphere of impartiality; on this occasion, we have decided not to use those terms. Cf. Valldecabres Ortíz, Ma. Isabel. Imparcialidad del juez y medios de comunicación, Valencia, Tirant lo Blanch, 2004, pp. 148 to 150. 7