The Manchester suicide bomber may have built a second device which is now in the hands of fellow jihadists, police fear.
Officers who raided the home of Salman Abedi discovered a working bomb factory with a huge stash of explosive chemicals and other components.
Security sources now believe that Abedi assembled the bomb himself after learning his trade in Libya.
But the amount of material in his home has led to fears that he could have built more than one device and and distributed them to other British-based extremists. A security source told the Telegraph: “The worry is there was enough to build two or three bombs and we can’t rule that out.”