consortium of private investors, and the company was listed on the London Stock Exchange in September 2003. In 2011 it was acquired by Cheung Kong Infrastructure Holdings. Group structure Northumbrian Water Limited (NWL) is a wholly owned subsidiary of Northumbrian Water Group Limited (NWGL). NWGL has two other direct subsidiaries, NWG Commercial Solutions Limited, which acts as a holding company for other non-regulated trading companies, and NWG Business Limited, which carries out non-household retail activities in England and in Scotland and to which NWL’s non-household customer base transferred at the opening of the market in April 2017 (except for customers who pre-registered to switch retailer upon the market opening). This chart shows the structure of the Northumbrian Water group (the Group) up to its ultimate parent, CK Hutchison Holdings Limited, a company listed on the Hong Kong Stock Exchange. The chart shows the principal intermediate holding companies, which are wholly owned unless otherwise shown. Northumbrian Water Limited NWL is by far the largest of NWG's subsidiaries. In 2010 it accounted for £657.8m out of the Group's total revenue of £704.7m (93%), and for £268.9m out of total operating profit of £275.8m (97%), and employed 2,930 of the Group's 3,105 employees (94%). NWL holds an Appointment under the Water Act 1989 as a water and sewerage undertaker. The Appointment covers two areas: water and sewerage services in the counties of Northumberland, Tyne and Wear, Durham and parts of North Yorkshire (including the Teesside conurbation), except for a small area around Hartlepool that is excluded from the water supply licence because it is still supplied by Hartlepool Water, a water-only company that is now owned by Anglian Water. water-only services in an area of eastern England covering part of the counties of Essex and Suffolk. Although the Instrument of Appointment covers both the northern and southern areas, for operational purposes NWL treats them as separate trading divisions, Northumbrian Water and Essex & Suffolk Water. Other activities NWG is involved in two projects to build and operate waste water treatment plants in Scotland, one at Levenmouth (Caledonian Environmental) and three in Ayrshire (Ayr Environmental). It also operates a waste water treatment plant for Cork City Council, in Ireland (Northumbrian Water Projects), and is the major partner in a joint venture with the Government of Gibraltar (AquaGib) that operates the territory's dual drinking water and sea water distribution systems. Other minor activities include consultancy