RADICAL government proposals to axe GCSEs and bring back O-levels risk "labelling teenagers as failures", school leaders have warned.

There are fears the move, which Wales education minister Leighton Andrews has said would not apply here, would lead to a two-tier system which writes off part of the population, according to headteachers' unions.

The plans, which would see the national curriculum in secondary schools scrapped, had come as a "complete bombshell", they said.

Shadow schools minister Kevin Brennan has been granted an urgent question in the Commons on the replacement of GCSEs, the scrapping of the secondary national curriculum, and the reform of exam boards.

Under the proposals, contained in documents leaked to the Daily Mail, pupils would begin studying "explicitly harder" exams in traditional academic subjects such as English, maths, history, modern languages and the sciences from 2014, with exams taken for the first time in 2016.

Papers would be set by a single exam board in order to provide a "gold standard" test across England, the documents said. It would mean that schoolchildren currently in Year 8, aged 12 and 13, would be the last to take GCSEs.

Less-able pupils will sit simpler examinations similar to the old CSEs. They will include simpler tests in English and maths in order to provide them with "worthwhile" qualifications.

Brian Lightman, general secretary of the Association of School and College Leaders (ASCL), suggested that an O-level system was inappropriate for today's education system.

"O-levels were an examination that existed for a small proportion of the population, that was part of the preparation for university," he said. "It was an academic qualification, and at the time when O-levels existed vast numbers of young people left either with no qualifications or ones that employers regarded as inferior. The last thing we want to do, when we are ambitious for our education service, is to create a two-tier system."

He added: "It does risk labelling teenagers as failures. In recent years we have done a lot to motivate children, to improve attendance, reduced disengagement and truancy, and this is key to the very real improvements that have taken place in schools."

It is understood that ministers believe that teenagers have been encouraged to think that a D, E, F or G grade at GCSE is a pass, when it is seen by many as a fail.