Dating game show 1990s
As documented in the Robert Redford film Quiz Show, Twenty-One in the USA caused the great "Quiz Swizz" when Charles van Doren was found to have been given the answers to questions in advance.
It's less well known that Twenty One was dropped by Granada in the UK when a contestant here also claimed that he had been given "definite leads" to the answers.
The BBC began the world's first high-definition, regular TV service from London in 1936.
Although there are still a few anomalies in the Scottish regions, in general all prime time game shows in the UK can be seen throughout the country. Associated Rediffusion, one of the ITV franchise companies, hit the big time with Take Your Pick, the first show to offer money prizes.
Its two defining characteristics were that it would carry commercials and be formed from a number of local companies.
This localised nature led to some game shows being shown in some parts of the country but not others, a situation which still exists today.
With Take Your Pick and Double Your Money maintaining their remarkable headlock on the audience figures until their unfortunate demise, very few other shows were able to get a look-in.
The introduction of a second BBC channel in 1964 did little to alter the outlook, since it had been created to provide alternative higher-brow programming than mere quiz shows, and for several years Call My Bluff was the channel's only game show of any note.