The Ants (unproduced TV story)
From Tardis Wiki, the free Doctor Who reference
The Ants was an unproduced story submitted on 16 January 1967 and written by Roger Dixon.
Synopsis
The TARDIS brings the Second Doctor and his companions to the Nevada Desert, where they discover they have been shrunk to a tenth of an inch in height. To make matters worse, they learn that the local ants have been made super-intelligent by atomic bomb tests and plan to take over the Earth. (DWMSE 4)