law: Prevention of Corruption Act, 1988
  21. Accused person to be a competent witness
  Any person charged with an offence punishable
  
  under this Act, shall be a competent witness for the defense and may give
  
  evidence on oath in disproof of the charges made against him or any person
  
  charged together with him at the same trial:
  Provided that-
  (a) he shall not be called as a witness except
  
  at his own request;
  (b) his failure to give evidence shall not be
  
  made the subject of any comment by the prosecution or give rise to any
  
  presumption against himself or any person charged together with him at the same
  
  trial;
  (c) he shall not be asked, and if asked shall
  
  not be required to answer, any question tending to show that he has committed
  
  or been convicted of any offence other than the offence with which he is
  
  charged, or is of bad character, unless-
  (i) the proof that he
  
  has committed or been convicted of such offence is admissible evidence to that
  
  he is guilty of the offence with which he is charged, or
  (ii) he has personally
  
  or by his pleader asked any question of any witness for the prosecution with a
  
  view to establish his own good character, or has given evidence of his good
  
  character, or the nature or conduct of the defense is such as to involve
  
  imputations on the character of the prosecutor or of any witness for the
  
  prosecution, or
  (iii) he has given
  
  evidence against any other person charged with the same offence.