America's first Secretary of Homeland Security is adamant - national security concerns must be weighed against the principles of democracy, even after the attack in Paris.

Tom Ridge told me the attack showed just how difficult it is to combat this kind of terrorism, from both an intelligence and a security point of view.

French intelligence is very good, he said, and these suspects were on police radars and yet it still happened.

But Mr Ridge also insisted that any effort by far right groups to isolate Muslims in general is counterproductive, integration, he said, is the only answer.