London Bombings

A previously unknown group, "Secret Group of Al Qaeda's Jihad in Europe," has claimed responsibility for four blasts that ripped through London during rush hour on Thursday morning, killing at least 45 people and disrupting a summit of the Group of Eight leaders in Scotland.

Witnesses saw the top ripped off a double-decker bus near Russell Square close to King's Cross train terminal, and three more apparently coordinated explosions caused carnage on packed subway trains as Londoners made their way to work.

Hear the latest news from London plus a big-picture analysis from some of the world's top terrorism experts.

Guests:

Rob Simon, defense and national security correspondent for the BBC

Rohan Gunaratna, head of terrorism research at the Institute of Defense and Strategic Studies.;
Louise Richardson, expert on international security and terrorist movements, author of "Five Degrees of Separatoin: Terrorists and Their Sponsors.";
Steve Simon, senior analyst at the RAND Corporation, author of "The Age of Sacred Terror: Radical Islam's War Against America." His forthcoming book is "The Next Attack.";
James Goddard, lives in the West London neighborhood.

Richard Heffernan, professor of government at the Open University of London.