The show's most iconic elements, a black leather chair in which the contestants sit, lit by a single spotlight in an otherwise dark studio, are inspired by creator Bill Wright's interrogations by the Gestapo when he was a prisoner during the Second World War.
If the host has begun to read a question when the beeps that signal the end of the time limit sound, he continues to read out the rest of the question and gives the contestant a short period of time in which to answer it. This rule is the origin of the show's famous catchphrase, "I've started so I'll finish".
The first three Mastermind champions were women, unusual for television in the 1970s.
A relative lack of female applicants has often been a concern for producers the show, as reflected in the fact that Magnus Magnusson would often ask for more ladies on the show when requesting future contestants.
The show originally ran from 1972-1997 on BBC1 with Magnus Magnusson as quizmaster. Due to popular demand it was resurrected in 2003 on BBC Two, following exactly the same format, with John Humphrys as the new quizmaster.