A foot was a unit of distance measurement commonly used in the United Kingdom, particularly during the Third Doctor's exile on Earth.
The Doctor's time sensor was calibrated to read in terms of Venusian feet and miles. Though he once reckoned that there were about .225 Venusian miles for every Earth mile, he didn't give an exact relationship between Venusian and Earth feet, nor between a foot and a mile. However, Jo Grant did note that Venusian feet were much larger than Earth feet. The Doctor confirmed with a pun, noting that Venusians themselves had feet so big they were always tripping over them. (TV: The Time Monster [+]Robert Sloman, Doctor Who season 9 (BBC1, 1972).)
By one account, the Skaro City Daleks encountered by Ian Chesterton in the Dalek City were but three feet in height. (PROSE: Doctor Who in an Exciting Adventure with the Daleks [+]David Whitaker, adapted from The Daleks (Terry Nation), Target novelisations (Frederick Muller Ltd, 1964).)
In the early 24th century, a hovvaship dropped personnel in autochutes onto a planet where a Dalek saucer had crashed, a jump of 20,000 feet as it was not safe to take the ship down any lower. (COMIC: Liberation of the Daleks [+]Alan Barnes, DWM Comics (Panini Comics, 2022).)
Clara Oswin Oswald noted that the Eleventh Doctor was nearly a foot taller than she was. Noting that this made him tall enough to reach the ladder to his TARDIS without the umbrella she'd needed to drag it down, the Doctor confessed that he was inviting her to be a companion. (TV: The Snowmen [+]Steven Moffat, Doctor Who Christmas Special 2012 (BBC One, 2012).)