The use of shackles in court has long been met with disapproval. (See People v. Harrington (1871) 42 Cal. 165.) See also Penal Code section 688: "No person charged with a public offense may be subjected, before conviction, to any more restraint than is necessary for his detention to answer the charge." The most significant reason is the inherent risk that "the shackling of a criminal defendant will cause prejudice . . . in the minds of the jurors. When a defendant is charged with any crime, and particularly if he is accused of a violent crime, his appearance before the jury in shackles is likely to lead the jurors to infer that he is a violent person disposed to commit crimes of the type alleged." (People v. Duran (1976) 16 Cal. 3d 282, 290 127 Cal. Rptr. 618, 545 P.2d 1322, 90 A.L.R.3d 1.) Shackling also is not condoned because it may impair a defendant's ability to participate in his or her defense. ( Id. at pp. 290-291.) "A defendant cannot be subjected to physical restraints of any kind in the courtroom while in the jury's presence, unless there is a showing of a manifest need for such restraints." (People v. Duran, supra, 16 Cal. 3d at pp. 290-291, fn. omitted.) Manifest need exists "only upon a showing of unruliness, an announced intention to escape, or 'evidence of any nonconforming conduct or planned nonconforming conduct which disrupts or would disrupt the judicial process if unrestrained . . . .' " ( People v. Cox (1991) 53 Cal. 3d 618, 651 280 Cal. Rptr. 692, 809 P.2d 351.) A manifest need showing does not have to be based on the conduct of the prisoner at the time of trial. ( People v. Livaditis (1992) 2 Cal. 4th 759, 774 9 Cal. Rptr. 2d 72, 831 P.2d 297.) Nor does it require a previous attempt by the defendant to disrupt courtroom proceedings or to escape from custody. (People v. Hawkins (1995) 10 Cal. 4th 920, 944 42 Cal. Rptr. 2d 636, 897 P.2d 574.) Restrictions on the use of shackling also apply at preliminary hearings absent some showing of necessity. (People v. Fierro (1991) 1 Cal. 4th 173, 220 3 Cal. Rptr. 2d 426, 821 P.2d 1302.) "The dangers of unwarranted shackling at the preliminary hearing are . . . not as substantial as those presented during trial. Therefore, a lesser showing than that required at trial is appropriate." (Ibid.)