Ofqual is pushing ahead with a plan to stop science practical work contributing to overall GCSE grades in the face of opposition from the government.

Education secretary Nicky Morgan has said the change that confines science assessment to written exam questions “was in danger of holding back the next generation of scientists”.

She wrote to Ofqual chief executive Glenys Stacey on Monday saying she “continued to share the concerns of many in the science community that not having an assessment of practicals… risks undermining the teaching of practicals in schools.”

“It is important you take all possible steps to mitigate that risk”, she added.

But the drive away from coursework came from her predecessor Michael Gove, who said in parliament in June 2013 he had “asked Ofqual to review the regulatory framework for GCSEs to judge how we might limit coursework and controlled assessment”.

He added that he had “listened to Ofqual when it argued that there should be an element of coursework to test bench skills – practical skills – in science, and I remain open to all the arguments”.

Ms Stacey said this week the exams the regulator had “consulted widely” on its practical assessment proposals for the new GCSEs in biology, chemistry, physics and combined science.

Currently, students complete a controlled assessment component by carrying out set practical work plus written work relating to it. This is worth 25 per cent of the student’s final grade.

But in future, students will instead be required to show their broad understanding of scientific experimentation during a written exam. At least 15 per cent of the total marks available in each GCSE are dedicated to this.

A minimum of eight practical activities in each individual science and 16 for combined science will still be specified by exam boards. Schools will be required to confirm that they have enabled their students to do the full range of practical work.

According to Ofqual, the new approach “will best balance our aims to encourage good scientific teaching” and had received “broad support” in its December assessment of practical work in the new science GCSEs consultation.

Ofqual now plans to consult on the rules and guidance. Exam boards will design the new specifications for the GCSEs against these rules, and the aim is to have specifications available for review from autumn 2015. Schools will start to teach them from September 2016, with the first exams in summer 2018.

A spokesperson for the Department for Education said: “Ensuring more young people continue to study science at A level and university and go on to get jobs in Britain’s thriving scientific sector is a vital part of our long-term economic plan.

“It is vital therefore that the qualification system supports practical science in schools which help make subjects come alive for pupils and can create a long-lasting love for the subject.

“It is crucial that the checks that will be established to ensure young people continue to undertake the full range of scientific practicals that will be required in the new GCSEs are robust, and we are pleased that Ofqual will be involving the scientific community in developing these arrangements.”