Michael Gove: education secretary says there’s a ‘compelling case’ for a move to A-levels with final exams. Photograph: Jonathan Brady/PA

The education secretary, Michael Gove, was 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 main overhaul of the system, AS-levels might be separated from A-levels to become a separate qualification.

Teenagers taking A-levels will not sit exams after 12 months, and should instead be tested on the end in their two-year course.

The proposals were specified by a letter from Gove to the exams regulator Ofqual.

In it, the education secretary says he has concluded there’s a compelling case for a move to A-levels with final exams.

But the shadow education secretary, Stephen Twigg, said Gove was “turning the clock back” and the proposal would chop young people’s options.

Brian Lightman, general secretary of the Association of faculty and school Leaders (ASCL), also sounded a note of warning, saying the union was not convinced that AS-levels needs to be a separate qualification.

In his letter, first reported inside the Daily Telegraph, Gove says the AS-level is considered a valuable qualification.

“i’ve concluded that it’s going to be retained, but that its design must be reconsidered to be able to establish it as a high-quality standalone qualification,” he says.

The new AS-level must be as intellectually demanding as an A-level and canopy half the content of an entire A-level. Students could take the qualification over one or two years, he adds.

On the way forward for A-levels, Gove says inside the letter: “Alongside a standalone AS-level qualification, I actually have concluded that the case for a completely linear A-level is compelling.”

The move will address concerns about pupils sitting exams in modules, and re-sits resulting in grade inflation, he argues.

“This may allow students to develop a stronger understanding in their subject throughout the greater maturity so that they can be developed over two years of analysis – something that i do know teachers believe may be particularly important for college students from disadvantaged backgrounds.”

The new A-levels could be taught from September 2015, a year later than the unique timetable of September 2014.

Twigg said: “Over again Michael Gove is all about turning the clock back. This plan would cut the choices for youngsters.”

He said there has been a necessity for more “high-quality options” available at 16, including all teens studying maths and English until 18.

Lightman said that preparation for university was “only 1 a part of the point of A-levels” and the qualification had “much more purposes than that”.

“Schools leaders could have no problem with adjusting or extending A-level specifications in order for on the highest levels these examinations prepare students for the main demanding university courses, but we aren’t convinced by the case for wholesale reform of this exam, that is a terribly successful qualification,” he said.

“The AS-level is valued in schools as a fashion of broadening the curriculum. We aren’t convinced that it will be a separate qualification.”

Under the present system, sixth-formers often sit four or five AS-levels, taking exams after 12 months before deciding which to drop and which to continue to A-level.

AS-levels, and both-stage system, were introduced by the last Labour government under the Curriculum 2000 reforms.

Gove’s new proposals effectively move the A-level system back to where it was before Curriculum 2000.

The plans, which come the day before the publication of GCSE and A-level league tables for schools in England, could raise concerns among some universities which use AS-level marks when making decisions about making offers for degree courses.

In his letter, Gove says there’s clear dissatisfaction among leading university academics about how A-level students are being prepared for further studies.

“i’m concerned that some natural science degrees are getting four-year courses to make amends for issues of A-levels. Linguists complain concerning the inadequacy of university entrants’ foreign language skills. Mathematicians are concerned that current A-level questions are overly structured and inspire a formulaic approach, in preference to using more open-ended questions that require advanced problem-solving.”

Gove also reveals that the Russell Group, which represents a collection of 24 leading universities, is to establish an organisation so that it will provide Ofqual with advice at the content of A-levels. It is going to consider the topics that are probably required to realize entry to a top university, he says.

Ofqual conducted a 3-month consultation into the way forward for A-levels last year. In November, the regulator announced plans to scrap January exams, and to provide students fewer chances to re-sit papers.