Education Secretary Michael Gove is to bring back traditional two-year A-levels with end-of-course exams in a major overhaul of the system.
AS-levels will be separated from A-levels to become a separate qualification, under plans that have been criticised for narrowing students' choices.
Teenagers taking A-levels will no longer sit exams after one year, and will instead be tested at the end of their two-year course.
The new proposals, laid out in a letter from Mr Gove to the exams regulator Ofqual, effectively move the A-level system back to where it was before Curriculum 2000, introduced under the last Labour government
Michael Gove has been criticised over the reform
In it, the Education Secretary says he has concluded that there is a "compelling case" for a move to A-levels with final exams.
But shadow education secretary Stephen Twigg said Mr Gove was "turning the clock back" and the plan would narrow young people's options.
Brian Lightman, general secretary of the Association of School and College Leaders (ASCL) also sounded a note of warning, saying the union was "not convinced" that AS-levels should be a separate qualification.
In his letter, first reported in the Daily Telegraph, Mr Gove says that the AS-level is regarded as a valuable qualification.
He says: "I have concluded that it should be retained, but that its design should be reconsidered in order to establish it as a high quality standalone qualification."
The new AS-level should be as "intellectually demanding" as an A-level, Mr Gove says, and cover half the content of a full A-level.
Students could take the qualification over one or two years, he adds.
On the future of A-levels, Mr Gove said: "Alongside a standalone AS-level qualification, I have concluded that the case for a fully linear A-level is compelling."
The move will address concerns about pupils sitting exams in modules, and re-sits leading to grade inflation, Mr Gove argues.
"This will allow students to develop a better understanding of their subject through the greater maturity that will be developed over two years of study - something that I know teachers believe can be particularly important for students from disadvantaged backgrounds."
The new A-levels will be taught from September 2015, a year later than the original timetable of September 2014.
Mr Twigg said: "Yet again Michael Gove is all about turning the clock back. This plan would narrow the options for young people."
He said there is a need for more "high quality options" available at age 16, including all young people studying maths and English until they are 18.
Mr Lightman said that preparation for university was "only one part of the purpose of A-levels" and the qualification had "far more purposes than that".
"The AS-level is valued in schools as a way of broadening the curriculum, we are not convinced that it should be a separate qualification."
Under the current system, sixth-formers often sit four or five AS-levels, taking exams after one year, before deciding which to drop and which to continue on to A-level.
The plans, which come the day before GCSE and A-level league tables for schools in England are published, could raise concerns among some universities who use AS-level marks when making decisions about making offers for degree courses.
In his letter, Mr Gove says there is "clear dissatisfaction" among leading university academics about how A-level students are being prepared for further studies.
"I am concerned that some natural science degrees have become four-year courses to compensate for problems with A-levels. Linguists complain about the inadequacy of university entrants' foreign language skills. Mathematicians are concerned that current A-level questions are overly structured and encourage a formulaic approach, instead of using more open-ended questions that require advanced problem-solving."
Mr Gove also reveals that the Russell Group, which represents a group of 24 leading universities, is to set up an organisation that will provide Ofqual with advice on the content of A-levels.
It will focus on the subjects which are most commonly required to gain entry to a top university, he said.
Ofqual conducted a three-month consultation into the future of A-levels last year.
In November, the regulator announced plans to scrap January exams, and to give students fewer chances to re-sit papers.
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