Game show in which contestants are tested in a variety of ways, ranging from physical fitness to intelligence

There were four players in each programme. Each player would be a different colour: red, blue, yellow or green. Each edition of the show consisted of six rounds as follows:

Mental Agility - The contestants are tested on how well they can manipulate information in their heads. How this is done would vary from programme to programme. Sometimes, the players were given an arrangement of playing cards to memorise. The questions would then be of the type: "What card was two to the left of the ace of spades?". Other times, the questions were the less complex (but just as difficult) maths questions, such as: "What is two to the power of five?".

Response - This was a test of the players' ability to respond to real-time events. In later series, this was done by putting the contestants into a professional British Airways flight simulator. The players had to land the plane on a runway. A graph would be plotted by the flight simulator's computer that would show the path taken by the player, as shown from above and the side. The contestants would be given points depending on how little they deviated from the proper course. The airports were always based on real ones, and in the grand final, the players would have to land a real plane.

Observation - In this round the players would be tested on how well they can recall visual information. They would be shown a short film on TV screens and they would be asked questions about it afterwards. Each contestant had a keypad which they would use to answer the multiple choice questions.

Physical Ability - As the title suggests, this was a test of physical ability. The players must race over a gruelling assault course. The first to get to the end gets the most points, that last gets the least. Women were always given a head start over the men.

Intelligence - A test of spatial awareness and the ability to work with abstract geometric shapes. The contestants were usually given 3D shapes that that were meant to be positioned in a particular way. A completely new puzzle was invented for every programme.

General Knowledge - The programme would end with a simple general knowledge quiz. Interestingly, each question would contain a key word from the question before.

For the last series, everything was changed. The observation round became a strange, abstract computer-generated cartoon. The response round featured players flying around unrealistic landscapes. And the intelligence round disappeared.

The Krypton Factor was presented by Gordon Burns and was made by Granada Television for ITV. In the final series, Penny Smith was a co-presenter. The programme ran from 1977 to 1995.