Wiktionary
n. shot in the dark
Wikipedia
Leap in the Dark was a British television anthology series with a supernatural theme. It was broadcast on BBC 2. It ran for 4 seasons - in 1973, 1975, 1977 and 1980 - and over 20 episodes were shown. The first season episodes were documentaries, seasons 2 & 3 were presented by Colin Wilson and consisted of docudramas re-enacting real-life cases of paranormal occurrences, and season 4 was original dramas, including episodes written by Alan Garner, Fay Weldon, and David Rudkin. Apart from the Pilot episode no episode of the first season exists complete due to wiping, and the episode The Battle for Miss Beauchamp in the 2nd season is also incomplete.
Usage examples of "leap in the dark".
An involuntary thrill of admiration for the man went through me at the manifestheroism of this leap in the dark.