Hyde Park bomb: Villiers calls for 'independent' investigation
25 February 2014 Last updated at 17:39 GMT
A man accused of four murders in an IRA bombing at Hyde Park will not be prosecuted, because he received a previous guarantee he would not be taken to court.
It follows a judge's ruling that an official assurance given in error meant the case could not proceed.
John Downey, 62, was accused of killing four soldiers in the attack in July 1982.
The Secretary of State for Northern Ireland, Theresa Villiers, said an independent investigation was now needed to understand what happened and make sure "lessons are learned".