He said he considered evacuating the capital, Tokyo, along with all other areas within 160 miles of the plant, and declaring martial law. “The future existence of Japan as a whole was at stake,” he said. “Something on that scale, an evacuation of 50 million, it would have been like a losing a huge war.”

http://www.telegraph.co.uk/news/worldnews/asia/japan/12184114/Fukushima-Tokyo-was-on-the-brink-of-nuclear-catastrophe-admits-former-prime-minister.html