The British government recently declared that one of the greatest threats to national security emanates from cyberspace. Hostile nation states are conducting a war over the internet, while Western companies face the wholesale plundering of their economic life-blood. There is increasing tension as China and the United States square up to each other, while North Korea and Iran are both thought to have launched attacks.

BBC Security Correspondent Gordon Corera reports from London, Washington and Beijing. He talks to those who are holding the line, including top intelligence officials, political leaders and the heads of some of the world's largest companies which stand to lose millions from the theft of their intellectual property. "Britain is under attack," says Britain's Foreign Secretary William Hague. "Most countries are under attack and certainly many industries and businesses are under attack." Who is responsible and where will it end?

Picture: Conservative South Korean activists denounce the North's cyber attacks, Credit: AFP/Getty Show less