A computer screen shows details of TalkTalk's login page on its web site in London
A computer screen shows details of TalkTalk's login page on its web site in London, Britain, October 26, 2015. British broadband provider TalkTalk said on Sunday it had hired defence company BAE Systems to investigate a cyber attack that may have led to the theft of personal data from its more than 4 million customers. TalkTalk said on Friday it had received a ransom demand from an unidentified party for the attack, which has led to calls for greater regulation of how companies and public bodies manage personal data. REUTERS/Stefan Wermuth