BT Group plc (trading as BT and formerly British Telecom) is a British multinational telecommunications holding company with head offices in London, United Kingdom. It has operations in around 180 countries and is the largest provider of fixed-line, mobile and broadband services in the UK, and also provides subscription television and IT services. BT's origins date back to the founding of the Electric Telegraph Company in 1846 which developed a nationwide communications network. In 1912, the General Post Office, a government department, became the monopoly telecoms supplier in the United Kingdom. The Post Office Act of 1969 led to the GPO becoming a public corporation. British Telecommunications, trading as British Telecom, was formed in 1980, and became independent of the Post Office in 1981. British Telecommunications was privatised in 1984, becoming British Telecommunications plc, with some 50 percent of its shares sold to investors. The Government sold its remaining stake in further share sales in 1991 and 1993. BT has a primary listing on the London Stock Exchange, a secondary listing on the New York Stock Exchange, and is a constituent of the FTSE 100 Index.