Education Secretary Michael Gove has been accused of narrowing young people's choices as he revealed plans to bring back traditional two-year A-levels with end-of-course exams.
Under a major overhaul of the system, AS-levels will be separated from A-levels to become a separate qualification. 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 proposals were laid out in a letter from Mr Gove to the exams regulator Ofqual. 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, he said: "Alongside a standalone AS-level qualification, I have concluded that the case for a fully linear A-level is compelling."
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 Gove told the education select committee: "I was worried that there was too much assessment and too little learning. It seemed to me that one of the most effective ways we could encourage the sort of deep thinking that we want to have in people, not just who are going on to university but who are going to be entering an increasingly testing and sophisticated world of work, was to move towards a linear A-level. But there are certain gains, of course, in the flexibility which the AS-level has given so we didn't want to completely abolish that. We thought the best way forward was a standalone qualification."