Ms Saunders, who is facing calls for her resignation, said she accepted the outcome of the review and would now be bringing a prosecution.
The case, expected to start on August 7, is set to be a “trial of the facts” without Lord Janner in court, deciding only if the peer committed physical acts of abuse.
Solicitor Liz Dux, who represents some of the alleged victims, said: "This is a vindication of our efforts to challenge the DPP's original decision not to charge Janner, which was clearly not in the interest of justice".
Lord Janner has been a prominent figure in the British Jewish community and served as Labour MP for Leicester West for 27 years.
His family have said he is “entirely innocent of any wrongdoing”.
