The structure of the quiz was relatively straightforward, with four “contenders” (rather than “contestants”) being given two minutes to answer as many questions as they could about a topic of their own choosing. These specialist subjects varied from the relatively conventional (“British moths,” “English cathedrals” or “the works of Dorothy L. Sayers”) to the more esoteric (such as “old time music hall” or “the Buddhist sage Niciren”). The general rule was that any subject was admissible as long as it was of a broadly academic nature and wide enough to provide scope for a torrent of exacting questions. After the specialist rounds, each of the four contenders were tested for a further two minutes in a similar fast-paced round of general knowledge questions, which seemed to get more difficult as the round wore on. The series as a whole was run on a knockout system, with highest scorers (and highest-scoring losers) progressing to later stages of the tournament. Winners were required to choose different specialist subjects when reappearing but were allowed to return to an earlier topic if they managed to get as far as the grand final. The eventual winner of the competition was presented with a special cut-glass bowl to take home.

The challenge facing the contenders was vastly intensified by the intimidating atmosphere that characterized the program. As well as having to maintain concentration in such daunting surroundings, participants were required to sit in an isolated pool of light in an intimidating black leather chair at the total mercy of the quizmaster. Audiences maintained complete silence as each contender faced a barrage of questions designed to reveal the depth (or lack thereof) of their knowledge. Even the opening title music, a piece by Neil Richardson titled “Approaching Menace,” was suitably threatening. The forbidding atmosphere of the program, with its spotlighted victim seated in a darkened room and exposed to intellectual torture, owed much to its creator, BBC producer Bill Wright. Wright had been a prisoner of war during World War II, and his idea for the program came out of his experience of interrogation by the German Gestapo, who had accused him of being a spy.

The presenter throughout the entire duration of the program was the Icelandic-born Scottish journalist Magnus Magnusson, who was already well known as a broadcaster on a variety of cultural topics. His politely sympathetic manner offered contenders some crumbs of reassurance, but once the stopwatch started, there was nowhere to retreat from his relentless inquisition. On occasion, it all proved too much, and some participants caved in completely, barely registering a score in the face of such pressure—acutely embarrassing, but certainly making for memorable television. One luckless participant in 1990 ended up with a record-low score of just 12 points. Magnusson’s catchphrases “I’ve started, so I’ll finish” (a mantra recited whenever the buzzer ending the round sounded in the middle of a question) and the formulaic reply “Pass” mouthed by participants when they did not know the answer were readily absorbed into everyday language.

Though initially considered to be too high-brow for peak-time audiences, the program escaped its latenight slot through a happy accident. When a Galton and Simpson comedy series called Casanova ’73 was removed from the schedule at short notice after BBC 1 Controller Bill Cotton Jr. and Director of Programs Alasdair Milne found opening episodes of the latter too offensive to be shown, Mastermind was put on in its peak-time slot as a short-term emergency replacement. The response was immediate, and the program’s right to a permanent place in the peak-time schedule was recognized. By 1974 Mastermind was topping the ratings alongside The Generation Game. By 1978 it was attracting audiences of 20 million.

Thus established, the program was henceforth run on an annual basis (with the single exception of 1982, when no contest was held). Despite the lack of big cash prizes and the fearsome grilling they stood to face, hundreds of people auditioned for the show each season. They came from a wide range of backgrounds, by no means all academic. Winners over the years ranged from Sir David Hunt (1977), who was a former ambassador to Brazil, to London taxi driver Fred Housego (1980), who capitalized on his newfound fame to appear in further quizzes and other programs, and train driver Christopher Hughes (1983). All winners automatically became members of the Mastermind Club, which staged annual reunions and a quiz of quizzes chaired by Magnusson himself. One exceptional Christmas show featured Magnusson himself in the chair, going through the ordeal he had presided over for so many years. Afterward, he freely admitted how demanding it was to be a contender and how much he admired those who had been through it before him.

The series was finally deemed to have run out of steam in 1997, after 25 years, and ended after a final contest filmed at St. Magnus Cathedral in Orkney. As well as all the usual spin-offs in the form of board games, books, and so forth, the program’s legacy may be detected in many subsequent shows, notably those in which contenders are asked seriously challenging questions in tense, hushed surroundings.

In November 2001, the black leather chair was dusted off once more for a revived version of the show to be screened on Discovery Channel, with Clive Anderson inheriting the post of quizmaster.

In June 2003, Mastermind was brought back on the air, showing on BBC 2 and hosted by John Humphrys.