The trial of six defendants, charged with conspiracy to murder and conspiracy to cause explosions in London on 21 July 2005, has heard the first evidence about the attempted bombing of Warren Street tube station. Also, the explosive used by the alleged bombers was powerful enough to kill - as powerful as TNT or gelignite.- a forensic expert told the court today. Claire McGavigan, a forensic scientist, said it was only faulty detonators that prevented a catastrophe.