London.

Our condolences go out to Londoners and Britons everywhere today.

As well as our admiration for their big brass ones (emphasis added).

At dusk, hundreds of thousands of Londoners began a long walk home, with the underground network that carries 3 million passengers a day closed at least until Friday.

Thomas Carr, a 63-year-old electrician who faced a two-hour walk home, said he would keep using the underground.

"It won't put me off using the Tube," he said. "You can't let them beat you."