O2 (UK) they can do it too" in reference to Vodafone and EE, O2's biggest competitors and the UK's top three mobile-telecoms companies. O2 (UK) Telefónica UK Limited (trading as O2 – stylised as O) is a telecommunications services provider in the United Kingdom, owned by the Spanish multinational Telefónica, and is headquartered in Slough. With 25 million subscribers (as of December 2017), O2 is the second-largest mobile network operator in the United Kingdom after EE, with Vodafone in third place. O2 was formed in 1985 as Cellnet, a 60:40 joint venture between BT Group and Securicor. In 1999, BT Group acquired
China Aerospace Science and Industry Corporation for the first time one of the Top 500 Brands with the Greatest Value in China with a rank of 46th. First established as the 5th Academy of the Ministry of Defense in October 1956, it went through numerous name changes including the Ministry of the 7th Machinery Industry, the Ministry of Aerospace Industry, the Ministry of Aviation and Aerospace Industry, China Aerospace Corporation, China Aerospace Machinery and Electronics Corporation in July 1999, and finally the present name China Aerospace Science & Industry Corporation in July 2001. CASIC owns seven academies, two scientific research and development bases, six public listed