Long-running quiz game in whch contestants are interrogated while sitting in the famous black chair

The format of Mastermind is famous for its simplicity. Each programme is half an hour long and features four contestants. The programme begins with a short introduction by the presenter. After this, he calls up the first player. When the person has sat down in front of him in the black chair, he will ask them for their name, occupation and specialist subject. Once the player has given his or her details, the questions on their specialist subject begin.

The player has to answer as many questions correctly as they can within the time limit. A counter appears in the corner of the screen that displays the number of questions that the contestant has answered correctly. There is no on-screen timer. Instead, the camera slowly zooms in on the contestant to give the viewer an indication of the amount of time remaining. If the player gives an incorrect answer, the presenter will tell them what the correct answer was. This has the effect of using up some of the player's time, which could be used to ask more questions. Instead of giving an incorrect answer, the player has the option of saying "pass", in which case, the presenter will go straight onto the next question. However, the pass tactic has a price. If two players get the same score at the end of a round, the one with the most passes will lose. Incorrect answers are not taken into account.

The specialist subject round takes up the first half of the programme. The final half of the programme is the general knowledge round. The format of the general knowledge round is exactly the same as the specialist subject round except that the questions could be on any subject instead of the player's chosen subject.

Each series of Mastermind uses a structure such that the four players in the final are the players that won each of the four semi-final and so on. The overall winner of the grand final gets a trophy and the title of Mastermind of the year that they won the programme.

Mastermind originally started in the 1970's and ran right up until 1997. During this first run, every edition of the programme was presented by Magnus Magnusson and the programme was shown on BBC 1. Five years after the first run ended, in 2002, a one-off celebrity special with Magnus Magnusson presenting was broadcast. In 2003, the programme made a proper comeback with a full series. This time, the programme was on BBC Two, and was presented by John Humphrys.

Special editions of the show featuring children and entitled "Junior Mastermind" began in 2004. These would be shown on consecutive weekdays and the final was shown in the weekend.