This is the nightmare scenario that nobody in British society wanted to face.

Anti-terrorism officers have not actually used the words in public, but the massive nationwide investigation into the London bombings is one now focused on suspected British suicide bombers who believe their faith justifies their actions.
But this is not just a nightmare in terms of the threat of violence from within, the fallout in the coming weeks and months will have the capacity to severely test - perhaps in some cases test to breaking point - the cohesion of British society.