integrated with those of the Post Office, which operated the UK's domestic telecommunications monopoly. In 1979, the Conservative Party government led by Margaret Thatcher began privatising the nationalised industries, and Cable and Wireless was an early candidate because of its history as a private company. The plan to privatise was announced in 1980. The government sold the first half of its share in Cable & Wireless in November 1981. In February 1982, the government granted a licence for a UK telecommunications network, Mercury Communications Ltd, as a rival to British Telecom. It was established as a subsidiary of Cable & Wireless. Seeing an opportunity to enter the growing US telecom market afforded by new, optical fiber technology (The US Communications Act of 1934 prohibited ownership of radio facilities by foreign owned companies), Cable & Wireless acquired 9xDS3s from MCI along the Amtrak right of way and began selling transmission services. Among its early customers was a company named TDX Systems. In 1986, the US long distance industry was deregulated, and many new companies launched into the equal access market. TDX Systems, based in Falls Church, Virginia, was one of these, with a footprint between Washington, DC and New York. TDX carried data (analog modem up to digital DS3), and built its own telephone switches at its engineering facility in Chantilly, VA. TDX voice switches, called "SSTs" (satellite switching terminal) were centrally controlled nationwide by Perkin-Elmer mainframes in Falls Church, and were some of the first long-distance switches to utilize least-cost routing, follow-on account codes and PINs. For a short time, TDX touted a position of being one of the primary providers of phone and data service for the World Trade Center. By 1987, TDX was rapidly expanding its leased fibre network westward, and by mid-1987 Cable and Wireless Communications plc had completed its purchase of the TDX network. For most of the late eighties, the long-distance company was named Cable & Wireless Communications, Inc, and the fibre/data business was named Cable & Wireless Management Services, Inc., until the two divisions were merged. The CWCI U.S. network expanded nationwide throughout the late eighties and nineties, serving all major and some smaller markets. In 1997, Mercury was merged with three cable operators in the UK (Vidéotron, Nynex, and Bell Cablemedia), and renamed Cable & Wireless Communications. Later that year, Cable & Wireless bought 49% of the Panamanian state-run INTEL (Instituto Nacional de