Extended projects will soon take over from general studies as A-level pupils' favoured means of broadening their education, heads said this week.
The prediction from John Dunford, Association of School and College Leaders general secretary, came as A-level general studies entries fell for a fifth year running.
The number of extended projects being completed rose by over 200 per cent to 15,958 in only the second year since the qualification was introduced.
"The extended project develops a wider range of skills in a way that general studies doesn't," Dr Dunford said.
"I think general studies was a good thing in its day but we are moving on. With the extended project counting as an AS-level for Ucas points, I think it will be almost universal in a few years' time."
The projects, also a compulsory part of the Diploma, were first available to take alongside A-levels from September 2008.
Typically they might involve pupils writing a 5,000-word dissertation, a report with findings from an investigation or study, completing a short film or composing a piece of music.
"It means greater breadth for what remains one of the narrowest post-16 education systems anywhere in the world," said Dr Dunford.
General studies was introduced in 1954 and by 1993 had grown to become the second most popular subject, sat by 54,000 pupils a year, with only A-level maths ahead of it.
With 46,770 candidates this year it is still the sixth most popular subject. But the 6.5 per cent fall in entries was the fifth biggest proportional decrease and means entries have fallen by more than 20 per cent since 2005.
Andrew Hall, director general of the AQA exam board, said: "It is down for the fifth year running, probably reflecting the fact that universities are not tending to accept general studies in the mix."
Last year Bristol University's head of admissions, Angela Milln, called on ministers to ensure that all schools offered extended projects as a way of combating a culture where pupils chased grades rather than knowledge.
200% - The year-on-year rise in the number of extended projects being completed.