Plans to remove the assessment of practical work from new science GCSEs has “great potential for damage”, a coalition of leading science organisations has warned.

Qualifications watchdog Ofqual has argued that its proposal for the reformed qualifications to be assessed entirely by written exam will improve the quality of practical science work in schools.

But a joint letter signed by the Wellcome Trust, one of the country’s biggest funders of science research, as well as the Nuffield Foundation, Gatsby Charitable Foundation and former government science adviser Sir John Holman, says the organisations are “deeply concerned” about the move. It could undermine efforts to promote STEM (science, technology, engineering and maths) subjects in schools, the statement adds.

“Without direct assessment, practical science may be devalued by head teachers and senior leaders who are under pressure from school accountability measures and tight budgets,” the letter says. “Given that nearly all students take science GCSEs, there is great potential for damage.

“There has been huge investment from government, industry and others to encourage the uptake of science, technology, engineering and mathematics. This risky proposal for GCSE science could seriously undermine these efforts.”

The organisations express reservations that practical skills “can be validly measured through questions in the written exam”.

“We urge Ofqual to delay any changes until evidence becomes available from the modifications that are being made to the assessment of practical science at A-level,” the letter adds.

Last month, Ofqual chief regulator Glenys Stacey told TES that practicals were “stultifying” for pupils and led to them practising only the narrow range of skills that were likely to be assessed, removing real experimentation from science.