The Trickster's World

The Trickster's World was an apocalyptic, alternative timeline, as identified by Clyde Langer, that was accidentally created by Sarah Jane Smith when the Trickster lured her back to 1951. (TV: The Temptation of Sarah Jane Smith)

Creation
This timeline was created when Sarah Jane travelled through a time fissure to 1951 Foxgrove and stopped her parents' deaths by using her sonic lipstick to damage their car. Though this change itself had no major effect on the timeline, as Foxgrove was a weak point on the Web of Time, the disturbance opened a rift that allowed the Trickster to break through into the universe and fully manifest on Earth. The Trickster then "sucked the life out of the Earth", reducing the planet to a dead wasteland and killing all but a few humans. It also affected her parents, who found their touch could cause things to decay, like flowers and fruit.

In this reality, London appeared to have become a blasted wasteland, with most buildings reduced to rubble. The sky was heavily clouded, and there was a blue-grey tinge to the atmosphere. The only inhabitants lived in a shanty town, where they were forced to mine Earth's remaining resources by Krislok, the Graske servant of the Trickster. The Trickster's eventual aim was to build ships, in order to escape into space and conquer the rest of the universe. (TV: The Temptation of Sarah Jane Smith)

Negation
Sarah Jane, Luke and Rani travelled back through the time fissure to 1951 Foxgrove, where Sarah Jane's parents discovered who she was. Sarah Jane then restored their car to working order and they drove it to their deaths. As a result, the alternate timeline in which the Trickster destroyed the Earth was negated, and the original timeline restored. (TV: The Temptation of Sarah Jane Smith)