The largest source of overseas-trained doctors had previously been south Asia, but recently there has been a sharp rise in doctors from southern Europe.
The GMC believes this might have been caused partly by changes to immigration rules which have made it more difficult for doctors from outside Europe to work here.
The economic downturn in southern Europe and the expansion of the European Union in eastern Europe are likely to have fuelled a 19 per cent increase in European Economic Area (EEA) trained doctors seeking to practise in the UK from 2010 to 2013.
The population of EEA graduates grew by far more than that of UK graduates and international medical graduates (IMGs) over the three-year period. But EEA graduates were still only a tenth of all doctors in 2013, whereas IMGs represented a quarter.
The report said: “Once, the main source of non-UK graduates was south Asia, particularly India, and to some extent the Middle East and Africa. Now, a third of the increase in non-UK graduates are from southern European countries.
“We do not know all the reasons for these changes but some are already clear – after changes to immigration rules in 2010 it became harder for international medical graduates to secure training and employment here.
“The data suggests that the economic downturn in the European Economic Area and the increased opportunity for EEA graduates in the new member states to work in the UK following enlargements in 2004 and 2007 are the main reasons for the increase in the proportion of EEA graduates working here.”
The report also found that a common theme among doctors working in primary care was feeling “overloaded” and “at risk of burning out”.
Meanwhile, there has been a rise in the number of women becoming surgeons and specialists in emergency medicine. The profession as a whole could soon have equal numbers of men and women – women already account for 44 per cent of all registered doctors (up from 42 per cent in 2010) and more than half of medical students are female.