By Pamela Barbaglia LONDON -France’s Thales is working on a plan to buy the cybersecurity business of IT consultancy group Atos, which could be worth about $3 billion, despite expectations of French government opposition to any break-up, sources told Reuters. Thales and its adviser Centerview Partners have approached several private equity firms including Bain Capital to explore a possible joint offer for Atos as part of a deal that would could see it broken up, the sources said. French defence group Thales would buy the big data and cybersecurity business, known as BDS , they told Reuters on condition of...