The GCSE was mooted in 1979 by Shirley Williams, then Labour education secretary, as evidence suggested that O-levels and CSEs could be combined successfully.
But Labour lost the general election and the project was shelved until Sir Keith Joseph, the Conservative education secretary, revived it in 1984. The first GCSE exams were taken in 1988.
Almost all subjects included for the first time a significant element of coursework, which in a few such as English and English literature counted for 100 per cent of the final mark.
Some teachers were initially nervous about school-based assessments that counted towards the GCSE, but many had become committed to the idea by 1991, when Prime Minister John Major ordered exam boards to limit coursework to 20 per cent.
Critics claimed coursework made GCSEs far too easy, and Mr Major embarked upon a campaign to raise standards which was also seen as an attempt to take on the educational establishment and, many thought, to lessen teachers' power.
In July 1991 he told a meeting of the right-wing think-tank, the Centre of Policy Studies: "It is clear that there is now far too much coursework, project work and teacher assessment.
"The remedy surely lies in getting GCSE back to being an externally assessed examination."
But by November his plans had taken a knock, as Lord Griffiths of Fforestfach, adviser to education secretary Kenneth Clarke, refused to keep to the 20 per cent limit and recommended that up to 40 per cent coursework be directed for some subjects.
In the end the figure settled at 30 per cent except in technology, where coursework counted for 60 per cent.
In 1992, teaching union conference delegates were already worried that coursework encouraged cheating.
Overall, GCSEs were deemed a success. The proportion of 16-year-olds staying on in full-time education was between 47 and 50 per cent from 1982 to 1987, but that rose steadily to 73 per cent in 1993 before settling between 70 and 72 per cent for the next 10 years.