Sir Ian Blair, head of the Metropolitan Police, told the BBC in a radio interview that investigators are "listening to some of them and watching some of them." But he said the big question is whether police have identified all of the terrorists active in the country.
"The threat is real," Blair said. "It's present with us."
Asked about the death of Brazilian electrician Jean Charles de Menezes, who was gunned down by police in the Stockwell Tube Station on July 22, Blair said that part of the context was that his department was dealing with "the greatest operational crisis it had ever known." The day before, London had been hit with virtual carbon copies of the July 7 bombings, except that the explosives proved to be duds that caused only minor damage.
"That's not an excuse, it's merely part of the context," he said.
Notable deaths of 2014 [PHOTOS]