Coldfire Construction was a construction company used by the Slitheen.
They built reactors in ten major cities across Earth which all had underground railways, namely London, Barcelona, Washington DC, Santiago, Los Angeles, Sydney, Beijing, Moscow, Naples, and Paris. These reactors would unite and black out the Sun. In London, they built several science buildings at various schools such as Park Vale Comprehensive School in Ealing and St. Cheldon's Comprehensive School in Upminster as well as schools in Epping, Amersham, Richmond, and Morden.
The secretary Janine had been killed by a member of the Slitheen. Sarah Jane Smith, Luke Smith, Maria Jackson and Clyde Langer stopped them, though. Soon after, Sarah Jane called UNIT so they would clear up all the Coldfire sites across the world. (TV: Revenge of the Slitheen)