Planet of Giants
Whilst trying to return Ian and Barbara to the twentieth century, The Doctor attempts an unorthodox new technique, causing the TARDIS doors to open in mid-flight, setting alarms ringing inside the craft.
Arriving on Earth, the time-travellers discover that they have all been reduced in size – they are now minute people in a world of giant objects. The TARDIS has landed them between the cracks in a garden patio – a garden teeming with giant worms, ants and cats. All deadly hazards for the miniature travellers.
To make matters worse, the TARDIS crew are caught up in the trials of a deadly new insecticide – DN6. A chemical so deadly that all insect life is threatened – a chemical that is also lethal to minuscule time-travellers…
This story was originally broadcast on BBC1 between 31st October and 14th November 1964.