By Michael Holden and William James LONDON (Reuters) – Britain said on Thursday it would rush through emergency legislation to force telecoms companies to retain customers data for a year, saying the move was vital to protect national security following a decision by Europes top court. Communication companies had been required to retain data for 12 months under a 2006 European Union directive which was thrown out in April by the European Court of Justice which said it infringed human rights. The scrapping of the directive could deprive police and intelligence agencies of access to information about who customers contacted by phone, text or email, and where and when, the British coalition government said. Prime Minister David Cameron stressed the emergency law would only restore existing powers and enshrine them in law, ensuring investigations would not be hampered and giving protection to the telecom firms from possible legal challenges.