It emerged in 2001 the Attorney General had referred a case to the police about British hostage-taking at the start of the Gulf War.
London-based organisation Indict spent five years compiling evidence of alleged war crimes and brutality by the Iraqi leadership.
A criminal case would focus on the plight of the 4,500 British citizens and thousands of people from other countries who were held hostage in the Gulf at the time.
It could eventually have led to a war crimes indictment against the Iraqi president, Saddam Hussein, and his deputy prime minister, Tariq Aziz.
But it was thought unlikely they would ever have been extradited for a trial before an international court.
Saddam Hussein was toppled from power in April 2003 during the US-led invasion of Iraq. He was subsequently captured after several months in hiding in December 2003. He was tried in an Iraqi court, sentenced to death and executed in December 2006.