The duty of Prosecuting Counsel is not to obtain convictions at all costs but to act as a Minister of Justice.
R. v. Puddick ER 176, 662 4 F. & F. 497. See also Randall v. R.  UKPC 19
"It cannot be over-emphasized that the purpose of a criminal prosecution is not to obtain a conviction; it is to lay before a jury what the Crown considers to be credible evidence relevant to what is alleged to be a crime. Counsel have a duty to see that all available legal proof of the facts is presented: it should be done firmly and pressed to its legitimate strength, but it must also be done fairly. The role of prosecutor excludes any notion of winning or losing; his function is a matter of public duty ... in civil life there can be none charged with a greater responsibility. It is to be efficiently performed with an ingrained sense of dignity."
- At all times maintain the honour and dignity of their profession;
- Always conduct themselves professionally, in accordance with the law and the rules and ethics of their profession;
- At all times exercise the highest standards of integrity and care;
- Keep themselves well informed and abreast of relevant legal developments;
- Strive to be, and to be seen to be, consistent, independent and impartial;
- Always protect an accused person's right to a fair trial, and in particular ensure that evidence favorable to the accused is disclosed in accordance with the law or the requirements of a fair trial;
- Always serve and protect the public interest;
- Respect, protect and uphold the universal concept of human dignity and human rights.
Prosecutors shall perform their duties without fear, favour or prejudice. In particular they shall:
- Carry out their function impartially;
- Remain unaffected by individual or sectional interests and public or media pressures and shall have regard only to the public interest;
- Act with objectivity;
- Have regard to all relevant circumstances, irrespective of whether they are to the advantage or disadvantage of the suspect;
- In accordance with the law or the requirements of a fair trial, seek to ensure that all necessary and reasonable enquires are made and the result disclosed whether that points towards the guilt or the innocence of the suspect;
- Always search for the truth and assist the court to arrive at the truth and to do justice between the community, the victim and the accused according to law and the dictates of fairness.