Formerly majority state-owned, the British government privatised the company in stages between 1979 and 1987. British Petroleum merged with Amoco in 1998, becoming BP Amoco plc, and acquired ARCO and Burmah Castrol in 2000, becoming BP plc in 2001. From 2003 to 2013, BP was a partner in the TNK-BP joint venture in Russia.