LONDON, July 21 (Reuters) - Britain’s BT has taken a multi-million pound stake in Silicon Valley cyber risk management firm Safe Security, underlining its ambition to target growth in the sector, a person familiar with the situation told Reuters. Making its first major investment in the cyber security since 2006, BT will be the largest investor in the latest round of funding for Safe Security which helps companies and governments gauge and mitigate cyber risk in real time by aggregating signals from people, processes and technology. It then quantifies the risk as a score and dollar value on its SAFE platform. Former chairman and CEO of Cisco John Chambers invested in the company’s $14 million series A funding, along with senior executives from SoftBank, Sequoia, PayPal, Adobe, and McKinsey & Co. The latest round is more than double the value of Series A, the source said. (Reporting by Paul Sandle; editing by Guy Faulconbridge)