A Charitable Earth

A Charitable Earth was a charity founded by a former companion of the Doctor called Dorothy. While looking up the Doctor's other companions, Sarah Jane Smith found out about Dorothy, discovering the charity had raised billions of pounds. (TV: Death of the Doctor)

As of 2010, the Sixth and Seventh Doctor's former companion Melanie Bush worked with A Charitable Earth, providing PCs to schools in Africa. (PROSE: Death of the Doctor)

Behind the scenes
"Dorothy" could refer to one of two known companions — Dorothea "Dodo" Chaplet, a companion of the First Doctor, and Ace, a companion of the Seventh Doctor whose real name was Dorothy. As the initials of A Charitable Earth spell "ACE", it is implied to be the latter who founded the organisation.