Teesside the four independent unitary authority boroughs of Hartlepool, Stockton, Middlesbrough and Redcar and Cleveland (a renamed Langbaurgh). At this time they were returned to the counties of North Yorkshire and County Durham for ceremonial purposes, with Stockton-on-Tees becoming the only district in England split between two ceremonial counties. In 1998 the neighbouring Borough of Darlington also became an independent unitary authority and this along with the four former Cleveland boroughs form the sub-region of the Tees Valley which is used for statistical purposes and governmental organisation. The name Tees Valley is increasingly promoted for economic and cultural connections, though Teesside,
Teesside EfW Cleveland. In December 2006, SITA UK signed a 28-year private finance initiative contract worth £70 million with Northumberland County Council, to provide them with waste management services and to reduce the county's reliance upon landfill. This included the construction of an extra incineration line at the Teesside plant. Civil construction of the extension began in April 2007, with heavy erection beginning that November. Von Roll was the general contractor for the entire extension. In May 2009, the third line, which cost £70 million to build, was brought into operation. It was officially opened on 8 October 2009 by former MP