[The June 2005 expulsion from Tanzania of] three...senior managers at City Water, a consortium responsible for managing Dar es Salaam's water supply...signalled the end of a flagship World Bank privatisation deal... And it marked the beginning of a legal action...[by] Biwater plc, the...company that led the consortium...against the government of one of the world's poorest countries... [T]he consortium's other partners were...Gauff and...Superdoll Trailer Manufacturing... [An] unpublished World Bank report said [of City Water], "The primary assumption...was that it would be very hard, if not impossible, for the private operator to perform worse than Dawasa [Dar es Salaam Water and Sewage Authority]. But that is what happened."... [W]ater prices [rose] sharply, yet there had been no discernible improvement in supply, reliability and quality... On May 13 2005, [Tanzania] decided to cancel City Water's contract... The company...[lodged a case] at...[an] affiliate of the World Bank, called the International Centre for Settlement of Investment Disputes... A decade ago, it would have been unusual for a company to launch a formal claim against a foreign government. What has changed that is the explosion in the number of bilateral investment treaties...[which] give commercial companies certain guarantees when they invest overseas...