7 July 2005 London bombings
Early on, there was a lot of confusion about what happened in the attacks. Police thought early on that military level plastic explosives were used.  As the explosions were thought to  happen at the same time, bombs with timed fuses might have been used. What the police thought changed as more information became available. Home-made organic peroxide-based explosives were used, according to a May 2006 report from the British government's Intelligence and Security Committee. The explosive was triacetone triperoxide.