The prize pot was increased by 50 after each incorrect answer.

The producers of the advert said the scene shown was of the teacher deliberately demonstrating an incorrect answer.

Where the document was an application form containing questions, it did not necessarily follow that an incomplete or incorrect answer would be material.

It found that 83 per cent had at times been unable to answer and 63 per cent admitted giving an incorrect answer to preserve their parental dignity.

If a player buzzed in with the incorrect answer, his opponent moved on to the endgame (rules of the endgame see below).