Epping

Epping was a town in Essex. A UNIT technician identified it as being in Sector 5. In 1970, a formation of Nestene spheres landed in nearby Oxley Woods. At the same time, the TARDIS materialised there, carrying the newly-regenerated Third Doctor. He was taken to Ashbridge Cottage Hospital by the UNIT troops who found him whilst searching for the "meteorites" (the spheres). (TV: Spearhead from Space)

Around 2008, the London branch of Coldfire Construction, which was secretly operated by the Slitheen, built a technology block in an Epping school, using it as a transducer to absorb energy from the Sun and destroy the Earth so they could sell it off. After Sarah Jane Smith foiled the Slitheen at Park Vale Comprehensive School Ealing, she called UNIT so they would clear up the Coldfire sites across the world. (TV: Revenge of the Slitheen)