Schools face five continuous years of exam reform, the qualifications regulator revealed today.

A further tranche of new GCSEs and A-levels is to be introduced to schools in 2017, Ofqual said. They will come in addition to the large numbers of reformed school exams announced for the previous two years, and mean that pupils will still be taking brand new A-levels and GCSEs for the first time in 2019.

Ofqual’s chief regulator, Glenys Stacey, said the aim was to not to burden the system with too much simultaneous change.

“We have had discussions with the secretary of state and the exam boards, holding the ring really, on what is a manageable next phase of reform,” she said. 

But teaching unions argue the pressure will still be too great. The timetable also means that schools will have to cope with using different GCSE grading systems - A*-G and 9-1 - for four years, between 2015-18. 

Mary Bousted, general secretary of the Association of Teachers and Lecturers union (ATL), said: “We are concerned that introducing such a huge raft of reforms to GCSEs and A-levels so quickly, and in a piecemeal fashion, will put massive pressure on teachers, the awarding bodies and Ofqual and risk jeopardising the reputation of GCSEs and A-levels.”

She added that pupils taking the qualifications for the first time “risk being severely disadvantaged since their teachers will have had little time to prepare for teaching both a new curriculum and helping students work for the new style exams”.

The final 2017 reforms are likely to include subjects like media studies and law. Ms Stacey, said: “There is a discussion to be had and a consultation to run about whether there is any line to be drawn about what is an A-level and what is a GCSE subject, but we are not proposing that as a threat to well-established subjects like media studies.”

The news came as more details of the earlier batches of reformed exams were revealed. Ofqual has sparked huge opposition among leading scientists, universities and teachers by deciding to overrule their objections and go ahead with a plan to stop practical work counting towards the main A-level grades in science subjects.

The watchdog, which wants to adopt similar arrangements in GCSEs, says new checks on schools and exam questions will actually improve the quality of practical science work in schools.

But it has failed to persuade its critics that assessing practicals with a separate pass or fail grade will not be damaging to the subjects.

Meanwhile the Department for Education unveiled details of “rigorous new content” for a batch of reformed A-levels to be introduced in 2015, and GCSEs, which will arrive in schools a year later.

At A-level, science and economics will have a greater demand for mathematical knowledge and skills. English literature candidates will have to study texts in greater depth, and there be “an ‘unseen text’ to ensure there is wider and more critical reading”.

The new history A-level will mean that pupils need to cover topics from a range of at least 200 years, rather than the current 100.

New science GCSEs will include “cutting-edge” topics such as the human genome and ecology in biology, nanoparticles in chemistry, and increased content on energy and space in physics, with more “mathematical challenge” across the board.

In reformed modern foreign language GCSEs, most exam questions will be asked in the language being studied.

Ofqual launched a consultation on the structure and assessment of new modern foreign language GCSEs today. The regulator intends to adopt a uniform format with reading, writing, speaking and listening components each accounting for a quarter of marks.

Ms Stacey described the current system as “higgledy piggledy” with variations between different languages and different exam boards. All new GCSE modern foreign languages will also have different tiers for pupils of different abilities under the Ofqual plan.

Tiering was a practice that education secretary Michael Gove said he wanted to end when he first set the current GCSE reforms in train, arguing that it represented a “cap on aspiration”.

But despite Ofqual’s commitment to introduce untiered GCSEs wherever possible, more than half of the subjects where new structures have been finalised will be tiered.

The regulator also confirmed today that the new geography GCSE will be exam-only, although fieldwork will remain compulsory, with the skills pupils learn through it assessed with written questions.

But heads’ union the NAHT has warned that the change will “simply reward the articulate over the practical”.

Conversely, Ofqual has suggested that fieldwork would be reintroduced into A-level geography and count for a fifth quarter of marks. But no final decision has been made and the introduction of the new qualification has been delayed until 2016.