Three-quarters of doctors struck off the medical register this year were trained abroad, according to new figures.
Of 39 that were struck off to September, 29 had their primary medical qualification (PMQ) outside Britain, including 12 in India, statistics from the General Medical Council (GMC) show.
Of 285 struck off since 2008, 194 had their PMQ overseas, including 64 in India.
The Sunday Telegraph, which obtained the statistics using freedom of information laws, said they would add to concerns that NHS patients are not protected adequately from health professionals from countries where training is less rigorous than in the UK and from those who are unfamiliar with basic medical practices in Britain.
The figures show that since 2008, 669 doctors have been either struck off or suspended by the GMC. Of these, 249 were British and 420 trained abroad.
The newspaper said that one third of doctors on the register were trained abroad, and two thirds trained in Britain.
GMC chief executive Niall Dickson said: "We absolutely acknowledge that when it comes to the serious end of the scale, those from overseas are more likely to appear, and we have set about a series of reforms to address this."
These include reviewing the Performance and Linguistic Assessments Board (PLAB) test for overseas doctors and a pilot induction programme for all new doctors, which is due to start early in the new year.
This aims to help doctors new to UK practice to understand the ethical and professional standards they are expected to meet.
Additionally, this month a new system of checks known as revalidation began. This means doctors in the UK are now legally required to show they are keeping up to date and are fit to practise.