A total of 4,700 pupils were on track to walk away with a U in GCSE science until a late intervention by Ofqual salvaged them grades, new figures show. 

On Monday the exam regulator announced it had taken the highly unusual step of intervening in GCSE combined science, after exam boards reported more pupils than expected were getting an unclassified result in the higher tier paper.

Ofqual lowered the “safety net” grade - the lowest possible grade that a candidate can get on the higher tier - to 3-3. It said it took the action because it looked like “in some cases students should have been entered for the foundation tier”.

According to figures published by the regulator today, 4,700 students achieved a 3-3 who sat the higher tier paper - about 3 per cent of all candidates who sat that tier.

However, 2,300 candidates (about 1.5 per cent of the higher tier) still got a U, even after Ofqual’s intervention.

Teacher unions blamed the government’s “rushed” exam reforms for the inappropriate entries to GCSE science which nearly resulted in pupils failing.  

They said that teachers had not been given enough time or support to help them make the right decisions about which tiers pupils should be entered for.