Figures handed to the Medical Programme Board, which oversees training in England, show 23% of the 6,000 trainees completing foundation years do not progress to core training.
Training campaign group Remedy UK say the figures suggest the EU working time directive, which limits doctors to a 48-hour week, has caused understaffing and additional stress to students.
Dr Shree Datta, chair of the BMA’s Junior Doctor Committee, said the figures were ‘alarming’ and could be caused by a number of factors.
‘The BMA estimates that one in four junior doctors have to work on understaffed rotas. Understaffing makes our work much more intense and does not go unnoticed by our patients,’ she said.
The figures could also be caused by a number of junior doctors continuing their studies in countries like Australia, she said.
‘We await the detailed analysis of these numbers but the possibility remains that the figures reported may not be painting an accurate picture of what is happening on the frontline.’