MI5 is taking the threat of Chinese hackers very seriously, it seems. They’ve taken the unprecedented step of sending a letter to 300 of the top Britishcompanies warning of the increased problems the hackers could cause. Part of the warning was printed on the Centre for the Protection of NationalInfrastructure site and read, “The contents of the letter highlight the director general’s concerns about the possible damage to UK business resulting from electronic attacksponsored by Chinese state organisations, and that the attacks are designed to defeat best-practice IT security systems. The letter acknowledges the strong economic and commercial reasons to dobusiness with China, but the need to ensure management of the risks involved." Several months ago hackers, believed to be from China, penetrated UK government servers, and are alsobelieved to be behind attacks on the US, Germany and France. There have also been attacks on several major companies like Rolls-Royce, according to the Times, but these are believed to be industrial spying.