Serco Group plc, through its subsidiaries, operates as a service company. It operates through four segments: Civil Government, Transport, Defence, and Science. Civil Government segment provides home affairs, education, health, local government, and consulting services. This segment also engages in managing prisons, electronically monitoring offenders, developing systems for law enforcement agencies, controlling immigration, and improving civil resilience; and in the provision of information technology-enabled services. Transport segment, through its partner, NedRailways, operates Merseyrail and Northern Rail in the United Kingdom. This segment also owns and operates the Great Southern Railway, including two trans-continental services, The Ghan and Indian Pacific in Australia. In addition, Transport segment involves in urban transportation business through the operation of the Docklands Light Railway, as well as provides traffic management systems. Further, this segment offers air traffic control services primarily in the United Kingdom, the Middle East, and the United States. Defense segment provides support services to the United Kingdom Ministry of Defence; marine services to the Royal Navy; and manages related training colleges. This segment also provides IT, engineering, logistics, and human resources services to the military; and supplies armed forces in Australia. Science segment operates national physical laboratory; and atomic weapons establishment, responsible for the stewardship of the United Kingdom’s nuclear deterrent. This segment also provides independent safety, risk management, and engineering services for the civil nuclear market; and support services to the European space agency and CERN. Serco Group also offers operational, management and consulting expertise in the aerospace, defense, education, health, home affairs, local government, science, technology, transport, and the commercial sectors. The company is based in Hook, the United Kingdom.